Basic Electronics
April 28, 2017 | Author: Brent Baldovino | Category: N/A
Short Description
Basic Electronics Reviewer for Everyone...
Description
I - VOLTAGE AND CURRENT 1. What is the color code for a 220
5% resistor?
Answer: Option D
5. Which resistive component is designed to be temperature sensitive?
A.
Red, Red, Brown, Gold
B.
Orange, Orange, Black, Gold
A.
Thermistor
C.
Red, Red, Black, Gold
B.
Rheostat
D.
Red, Red, Brown, Silver
C.
Potentiometer
D.
Photoconductive cell
Answer: Option A Explanation: Resistor colour coding series: Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Gray 8 White 9 None 20% Silver 10% Gold 5% Therefore Red, Red, Brown, Gold 2 2 101 5% = 22 x 10 = 220 ohm 5% (tolerance).
2. If 60 J of energy areevery 15 C of charge, what is the voltage? A.
4V
B.
60 V
C.
15 V
D.
0.25 V
Answer: Option A
3. An atom's atomic number is determined by the number of: A.
neutrons minus protons
B.
protons
C.
electrons
D.
neutrons
Answer: Option B
4. A voltage will influence current only if the circuit is: A.
open
B.
insulated
C.
high resistance
D.
closed
Answer: Option A
6. The battery symbol is: A.
B. C. D.
Answer: Option B
7. What type of switch is this?
A.
push button
B.
SPST
C.
DPDT
D.
SPDT
Answer: Option D
8. Primary batteries, unlike secondary batteries, may be: A.
charged once
B.
used once
C.
recharged over and over
D.
stored indefinitely
Answer: Option B Explanation: Primary batteries (disposable batteries), which are designed to be used once and discarded when they are exhausted. Secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times.
9. In practical applications, battery
voltage: A.
is restored as soon as disconnect occurs
B.
is lowered as the load increases
C.
may be stored indefinitely
D.
will be reduced to zero as power is drawn
Answer: Option B
10. The negative and positive charge symbols are assigned (in that order) to the: A.
proton and electron
B.
electron and proton
C.
atom and nucleus
D.
electron and element
Answer: Option B
11.
A voltmeter is used: A.
to measure current
B.
in series with the circuit
C.
in parallel with the circuit
D.
to measure coulombs
A.
Ampere, A
B.
Coulomb, I
C.
Ampere, Q
D.
Ampere, I
Answer: Option D
15. Which part of an atom has no electrical charge? A.
Electron
B.
Neutron
C.
Proton
D.
All of the above
Answer: Option B
16. Which voltage source converts chemical energy to electrical energy? A.
Electrical generator
B.
Battery
C.
Solar cell
D.
Electronic power supply
Answer: Option B
17. An example of potential energy is: Answer: Option C
12. If the current in a circuit equals 0 A, it is likely that the A.
voltage is too high
B.
resistance is too low
C.
circuit has a short
D.
circuit is open
Answer: Option D
13. Current equals:
coulombs × time
C.
D.
tea-kettle steam
B.
a moving vehicle
C.
the sun
D.
a battery
Answer: Option D
18. If 40 C of charge flow past a point in 20 s, what is the current? A.
2A
B.
0.5 A
C.
20 A
D.
40 A
Answer: Option A
A.
B.
A.
voltage × time
Answer: Option A
14. What are the unit and symbol for current?
19. Batteries differ from fuel cells in that A.
a battery is a closed system
B.
a battery uses hydrogen and oxygen to create electricity
C.
a battery uses a polymer electrolyte membrane
D.
none of the above
Answer: Option A
20. The removal of a non-neutral subatomic particle converts the atom into a: A.
charged ion
B.
nucleus
C.
heavier element
D.
compound
Answer: Option C
26. Which unit of charge contains 6.25 × 1018 electrons? A.
An ampere
B.
A coulomb
C.
A volt
D.
A joule
Answer: Option B Answer: Option A 27. A switch is a device that: 21. One coulomb passing a point in one second is one: A.
ampere
B.
volt
C.
ohm
D.
charge
A.
short circuits complex circuits
B.
holds a fuse
C.
has double poles
D.
opens or completes a current path
Answer: Option A Answer: Option D 22. In which states may matter may be found? A.
solid, liquid, or mineral
B.
solid, gas, or liquid
C.
mineral, gas, or liquid
D.
plastic, solid, or gas
28. The term used to designate electrical pressure is: A.
voltage
B.
current
C.
resistance
D.
conductance
Answer: Option A
29. Which electronics material opposes the movement of free electrons?
Answer: Option B
23. Material that consists of a mixture of elements is considered to be: A.
an element
B.
an ion
C.
a compound
D.
a molecule
A.
Conductor
B.
Insulator
C.
Semiconductor
D.
Element
Answer: Option B
30. Current is considered as the movement of:
Answer: Option C
24. How many valence shell electrons are there in semiconductor atoms? A.
16
B.
8
C.
4
D.
2
Answer: Option C
25. When considering conventional current versus electron current flow:
A.
electrons
B.
protons
C.
charge
D.
nuclei
Answer: Option A
31. A lead-acid battery is an example of a A.
solar cell
B.
fuel cell
A.
electron current flow came first
C.
primary battery
B.
protons move in conventional current flow
D.
secondary battery
C.
conventional current flow came first
D.
the direction of current is the same in both methods
Answer: Option D
32. The charge of one coulomb is equal to: A.
6.24 x 10−18 electrons
B.
one ampere
C.
one second
D.
6.24 x 1018 electrons
38. If a fluid system is compared to an electrical system, the fluid pump will correspond to a:
Answer: Option D
A.
conductor
B.
lamp
C.
battery
D.
insulator
Answer: Option C 33. A basic electric circuit is made up of what components? A.
A load, a resistor, and a conductive path for current
B.
A voltage source, a load, and a conductive path for current
C.
A voltage source, a conductive path for current, and a battery
D.
A conductive path for current, a battery, and a copper wire
39. An element is a substance that is: A.
varied throughout the entire piece
B.
used only in electronics
C.
electrically charged
D.
found only in its pure form
Answer: Option D
40. Current is: Answer: Option B
34. An ammeter is used to measure A.
voltage
B.
current
C.
resistance
D.
All of the above
35. What is the name of the pressure that moves electrons in a closed circuit? A.
amperes
B.
ohms
C.
voltage
D.
coulombs
Answer: Option C
36. What is a characteristic of a secondary cell? rechargeability
B.
not rechargeable
C.
a dry cell
D.
non-liquid
Answer: Option A
37. What are the basic building blocks that all matter is composed of? A.
electrons, neutrons, and protons
B.
two protons for each neutron
C.
two protons for each electron
D.
electrons, neutrons, and charged ions
Answer: Option A
the presence of a positive charge
B.
the abundance of electrons
C.
the movement of electrons
D.
the repulsion of electrons
Answer: Option C
Answer: Option B
A.
A.
41. What do you call a diagram that shows the electrical connections of a circuit's components? A.
A schematic diagram
B.
A pictorial diagram
C.
A block diagram
D.
An electrical diagram
Answer: Option A
42. A short circuit will have: A.
a small current flow
B.
a large current flow
C.
no current flow
D.
some current flow
Answer: Option B
43. The basic difference between a fuse and a circuit breaker is A.
a fuse is slower
B.
a fuse is reusable
C.
a circuit breaker is reusable
D.
a circuit breaker is more reliable
Answer: Option C
44. Which is the smallest? A.
atom
B.
proton
C.
neutron
D.
electron
C.
3A, 3A, 3A
D.
3A, 2A, 1A
Answer: Option A Explanation: V = IR
Answer: Option D
V = I(R1 + R2 + R3) 45. A secondary cell generates dc via chemical activity; a primary cell generates dc: A.
electrically
B.
thermally
C.
optically
D.
chemically
I = V/(R1 + R2 + R3) = 9/(3 + 3 + 3) = 9/9
Answer: Option D 46. Which of the following statements is true? A.
Unlike charges repel and like charges attract.
B.
Like charges repel and unlike charges attract.
C.
Unlike charges attract and like charges attract.
D.
Like charges repel and unlike charges repel.
= 1 Amp.
2. One of the most common applications of a potentiometer is as an ad also known as A.
voltage control
B.
current control
C.
volume control
D.
divider control
Answer: Option C
Answer: Option B
47. If an electrical system is compared to a fluid system, the electrical current corresponds to the:
3. If the resistance total in a series circuit doubles, current will: A.
be the same
A.
pressure
B.
pump
B.
be doubled
C.
water wheel
D.
water flow
C.
reduce source voltage
D.
be halved
Answer: Option D _________________________________________ _________________________________________ II - Series Circuits 1. What is the current flow through R1, R2, and R3?
Answer: Option D
4. Power is defined as: A.
the rate at which work is done
B.
work
C.
the conversion of energy
D.
joules
Answer: Option A
5. What is the dc source voltage?
A.
1A, 1A, 1A
B.
1A, 2A, 3A
8.
A.
78 V
B.
39 V
C.
13 V
D.
0V
Answer: Option A
In the given circuit, what type of failure will cause the voltage at po at point C? A.
R1 shorts
B.
R2 shorts
C.
R3 shorts
D.
R2 opens
Answer: Option B
6. With a total resistance of 3300 ohms and a 45 V source, if R 3 is 1200 ohms, what will be its 9. voltage drop? A.
16.36 V
B.
32.72 V
C.
10.90 V
D.
15.00 V
Answer: Option A What is the voltage at points B to D in the given circuit?
7.
A.
+19.2 V
B.
+8.8 V
C.
+28 V
D.
–19.2 V
Answer: Option A
10.
Calculate the voltage at point B in the given circuit. A.
+10.48 V
B.
+0.94 V
C.
+2.6 V
D.
+3 V
Answer: Option A Calculate the voltage at point C in the given circuit. A.
+1.48 V
B.
+0.94 V
C.
+11.6 V
C.
voltage is reduced
D.
+3 V
D.
resistance is doubled
Answer: Option C
Answer: Option A
15. What are the minimum and maximum output voltages?
11. An 8-ohm resistor is in series with a lamp. The circuit current is 1 A. With 20 V applied, what voltage is being allowed for the lamp? A.
4V
B.
8V
C.
12 V
D.
20 V
Answer: Option C
12. What is wrong, if anything, with this circuit?
A.
0 V, 4 V
B.
0 V, 8 V
C.
0 V, 12 V
D.
0 V, 16 V
Answer: Option D 16. A short circuit has:
A.
R1 is open.
B.
R1 is shorted.
C.
R2 is open.
D.
R2 is shorted.
Answer: Option B
13. Kirchhoff’s voltage law states that: A.
the sum of the voltage drops in a series circuit is equal to the total applied voltage
B.
the algebraic sum of the resistances is equal to the sum of the voltages
C.
the algebraic sum of the individual currents around a closed loop is zero
D.
the voltages developed across each element in a series circuit are identical
Answer: Option A
14. If series current doubles, then: A.
resistance is halved
B.
voltage is doubled
A.
too much resistance
B.
no conductance
C.
no resistance
D.
low current
Answer: Option C
17. If three resistors of 1.5 kilohms, 470 ohms, and 3300 ohms are in series with a 25-volt source, what is the total circuit current? A.
210 mA
B.
5.2 mA
C.
4.7 mA
D.
.007 A
Answer: Option C
18. What is the total power in the circuit?
the given circuit, which resistors will carry current? A.
All twelve resistors will carry current.
B.
Only R6 and R11 will carry current.
C.
Only R2, R4, R6, and R11 will carry current.
D.
Only R3, R6, R9, and R12 will carry current.
Answer: Option C A.
170 mW
B.
1.7 W
C.
17 W
D.
170 W
Answer: Option A
19. A string of resistors in a series circuit will: A.
divide the source voltage in proportion to their values
B.
reduce the power to zero
C.
cause the current to divide
D.
increase the source voltage in proportion to the values
Answer: Option A
20.
22. Given a series circuit containing resistors of different values, which statement is not true? A.
The current through each resistor is the same.
B.
The sum of the voltage drops across each resistive element will be equal.
C.
The total resistance is the sum of the value of the resistors.
D.
The voltage drop across each resistor is the same.
Answer: Option D
23. With 20 V applied, an 8-ohm resistor is in series with a lamp. When the lamp is removed, what voltage will be read across the lamp socket? A.
0V
B.
8V
C.
12 V
D.
20 V
Answer: Option D While putting three 1.5 V batteries into a flashlight, you put one in backwards. The flashlight will be ______________. A.
brighter than normal
B.
dimmer than normal
C.
off
D.
the same
Answer: Option B 21.
24. When 50 V is applied to four series resistors, 100 µA flows. If R1 = 12 k , R2 = 47 k , and R3 = 57 k , what is the value of R4? A.
38.4 k
B.
3.84 k
C.
384 k
D.
3.84 M
Answer: Option C
25.In a series circuit, the voltage measured across a short will be: A.
source voltage
B.
infinite voltage
C.
zero volts
D.
the normal voltage drop
Answer: Option C
If a voltage is connected between contacts 2 and 3 in
26.
opposing, what is the total voltage? A.
11 V
B.
16 V
C.
21 V
D.
80 V
Answer: Option A
30. What is the total resistance?
Which is a true statement about the circuit in the given circuit? A.
The batteries are series-aiding and the total source voltage equals 21 V.
B.
The batteries are series-opposing and the total source voltage equals 3 V.
C.
The batteries are series-aiding and the total source voltage equals 3 V.
D.
The batteries are series-opposing and the total source voltage equals 21 V.
Answer: Option B
27. A series circuit current:
A.
0k
; there is no current
A.
remains the same through each component
B.
2k
; the average
B.
is the same as the individual resistances
C.
3k
; the largest
C.
is subtracted by each component
D.
6k
; the sum
D.
varies through each component
Answer: Option D
Answer: Option A 31. Which equation determines individual resistor voltage drop?
28.
A.
VxR
B.
I2 x R
C.
VxI
D.
IxR
Answer: Option D
32. How will an open resistor affect a series circuit? If R2 opens in the given circuit, what is the voltage at point B?
A.
Current will flow around the open resistor.
A.
+19.2 V
B.
The open resistor will drop 0 V.
B.
+8.8 V
C.
Total resistance will decrease.
C.
+28 V
D.
No current will flow in the circuit.
D.
–19.2 V
Answer: Option D
Answer: Option C 33. The voltage drop across a series resistor is proportional to what other value? 29. If 5 V and 16 V power supplies are connected in series-
A.
total resistance
C.
512 mW
B.
its own resistance
D.
1024 mW
C.
wattage rating
D.
the amount of time the circuit is on
Answer: Option B
Answer: Option C
39. A series circuit schematic is recognized because all the components are connected:
34. Resistance in a series circuit will: A.
control the voltage
B.
double the current
C.
halve the power
D.
oppose current
Answer: Option D
primary/secondary difference
B.
total resistance
C.
the polarity connections
D.
average resistance
Answer: Option B
diagonally across the page
B.
in a uniform vertical manner
C.
end to end in a "string"
D.
horizontally across the page
Answer: Option C
40. With a 900 V source, voltage is divided across 3 series resistors of 300 V, 280 V, and:
35. When a battery is connected to a series circuit, it delivers current based only upon: A.
A.
A.
30 V
B.
270 V
C.
320 V
D.
900 V
Answer: Option C
41.
36. What determines the total resistance in a series circuit? A.
the largest resistor
B.
the sum of the resistors
C.
the largest resistor minus the smaller
D.
the smallest resistor
Answer: Option B
37. If two resistors have the same voltage drop in a series circuit, it means:
How much current flows in the circuit in the given circuit? A.
20
A
they are of unequal value
B.
60
A
C.
the voltage has doubled
C.
80
A
D.
they are of equal value
D.
140
A.
they are connected in parallel
B.
Answer: Option D
38. If series resistors dissipate 16 mW, 107 mW, 146 mW, and 243 mW, what is the total power consumed by the circuit? A.
128 mW
B.
269 mW
A
Answer: Option A ________________________________________ _______________________________________
III - PARALLEL CIRCUITS 1. When parallel resistors are of three different values, which has the greatest power loss?
A.
The smallest resistance
D.
B.
The largest resistance
C.
They have the same power loss.
D.
Voltage and resistance values are needed.
more than one path for current flow
Answer: Option D
8.
Answer: Option A
2. What is the product-over-sum result of 150 and 6800? A.
150
B.
146.7
C.
0.006
D.
6800
Answer: Option B
3. The voltage across any branch of a parallel circuit: A.
varies as the total current varies
B.
is inversely proportional to total circuit resistance
C. D.
In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to the speakers. How much total current is the amplifier providing to the speakers? A.
0A
B.
1.5 A
is equally applied to all branch conductances
C.
3A
is dropped in proportion to each branch resistance
D.
More information is needed to find the total current provided to the speakers.
Answer: Option C
Answer: Option C
4. What is the total power loss if 2 k and 1 k connected resistors have an ITof 3 mA? A.
6
W
B.
36
C.
6 mW
D.
36 mW
parallel-
W
9. If two parallel-connected resistors dissipate 6 watts and 10 watts of power, then what is the total power loss? A.
3.75 watts
B.
4 watts
C.
16 watts
D.
60 watts
Answer: Option C Answer: Option C 5.
What happens to total resistance in a circuit with parallel resistors if one of them opens? A.
It increases.
B.
It halves.
C.
It remains the same.
D.
It decreases.
1 Which component is shorted? 0.
Answer: Option A
6. Components that connect in parallel form: A.
branches
B.
open circuits
C.
short circuits
D.
a voltage divider
A.
R1
B.
R2
C.
R3
D.
R4
Answer: Option D Answer: Option A
7. A parallel circuit differs from a series circuit in that a parallel circuit has A.
no path for current flow
B.
fewer paths for current flow
C.
one path for current flow
11. 1 4.
What does VS equal in the given circuit? A.
0V
B.
9V
What would these meter readings indicate about the circuit in the given circuit?
C.
27 V
Meter Readings: I = 7.6 mA, V = 12 V
D.
More information is needed to find VS.
A.
R1 is open.
B.
R2 is open.
C.
The fuse is open.
D.
The circuit is operating normally.
Answer: Option B
15. The current through R1 will be:
Answer: Option B
12. A.
128 mA
B.
88 mA
C.
48 mA
D.
2.2 mA
Answer: Option C
16. The voltage read by the voltmeter will be:
In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to the speakers. How much total power is the amplifier delivering to the speakers? A.
0W
B.
18 W
A.
24 V
B.
12 V
C.
36 W
C.
6V
D.
4V
D.
More information is needed to find the total power delivered to the speakers.
17. Which component is of the wrong value?
Answer: Option C
13. If a 1 k and a 2 k resistor are parallel-connected across a 12 V supply, how much current is received by the 2 k resistor? A.
4 mA
B.
6 mA
C.
8 mA
D.
12 mA
Answer: Option B
Answer: Option B
B.
8 ohms and 16 ohms
C.
10 ohms and 20 ohms
D.
12 ohms and 24 ohms
Answer: Option D
21. When a parallel 5 k power loss?
resistor and a 25 k
resistor have a 10 V s
A.
2.4 mW
B.
3.3 mW
C.
24 mW
D.
33 mW
Answer: Option C
22. In a parallel resistive circuit:
A.
R1
B.
R2
C.
R3
D.
R4
A.
there is more than one current path between two points
B.
the voltage applied divides between the branches
C.
the total branch power exceeds the source power
D.
the total circuit conductance is less than the smallest branch conductance
Answer: Option A
18. Answer: Option A
23 What is the total resistance? .
What does I3 equal in the given circuit? A.
5 mA
B.
45 mA
C.
50 mA
D.
100 mA
A.
7k
B.
1k
C.
706
D.
353
Answer: Option D Answer: Option A 24. Kirchhoff's current law for parallel circuits states that the:
19. What is the total power of the circuit?
A. C.
2.2 W 6.2 W
Answer: Option B
B. D.
A.
sum of all branch voltages equals zero
B.
total circuit resistance is less than the smallest branch resistor
C.
sum of currents into a junction is equal to the difference of all the branch currents
D.
sum of the total currents flowing out of a junction equals the sum of the total currents flowing into that junction
4.2 W 8.2 W
Answer: Option D
20. What are the individual values of two parallel resistors whose R2T is 8 ohms, when one has Which component is open? double the resistance of the other? A.
2.7 ohms and 5.3 ohms
5.
2 8.
A.
R1
B.
R2
C.
R3
D.
R4
Answer: Option C
2 6. What would these meter readings indicate about the circuit in the given circuit? Meter Readings: I = 10 mA, V = 12 V A.
R1 is open.
B.
R2 is open.
C.
The fuse is open.
D.
The circuit is operating normally.
Answer: Option D What would these meter readings indicate about the circuit in the given circuit?
2 9.
Meter Readings: I = 0 mA, V = 0 V A.
R1 is open.
B.
R2 is open.
C.
The fuse is open.
D.
The circuit is operating normally. What does RT equal in the given circuit?
Answer: Option C
27. If 550 mA of current leaves a node that had 250 mA entering from one branch, how much current would enter from the other? A.
250 mA
B.
300 mA
C.
550 mA
D.
800 mA
Answer: Option B
A.
90
B.
180
C.
200
D.
1.8 k
Answer: Option A
30. What procedure should be followed when troubleshooting with an ammeter or voltmeter? A.
Short the leads and adjust.
B.
Check the meter’s external power supply.
C.
Start with the highest scale and adjust down to a lower scale.
D.
Start with the lowest scale and adjust up to a higher scale.
Answer: Option C
31. A parallel circuit is also used as a divider for:
A.
conductance
B.
voltage
C.
power
D.
current
3 6.
Answer: Option D
32. What is RT for a 12 k in parallel?
,a4k
, and a 3 k
A.
1.5 k
B.
2k
C.
6.3 k
D.
19 k
resistor
What does R1 equal in the given circuit?
Answer: Option A
33. What is the total resistance of four 1 k connected resistors?
parallel-
A.
200 ohms
B.
250 ohms
C.
400 ohms
D.
4 kilohms
Answer: Option B
A.
90
B.
180
C.
200
D.
1.8 k
Answer: Option B
37 What is the total resistance? .
34. Which are the better test devices used to isolate a suspected open component within a parallel circuit? A.
a voltmeter or an ohmmeter
B.
neither an ammeter nor a voltmeter
C.
a wattmeter or a voltmeter
D.
an ammeter or an ohmmeter
Answer: Option D
3 5.
What does P2 equal in the given circuit? A.
45 mW
B.
405 mW
C.
450 mW
D.
900 mW
Answer: Option B
A.
1.045 k
B.
1.545 k
C.
2.045 k
D.
2.545 k
Answer: Option B
38. What is RT for fifteen 2 M parallel?
resistors all connected in
A.
133 k
B.
300 k
C.
750 k
D.
30 M
Answer: Option A
39. Which is considered to be the common reference for a parallel circuit? A.
Voltage
B.
Current
C.
Power
D.
Resistance
Answer: Option A
IV - Series-Parallel Circuits 1. What theorem replaces a complex network with an equivalent circuit containing a source voltage and a series resistance? A.
Multinetwork
B.
Norton
C.
Thevenin
D.
Superposition
Answer: Option C
A.
individual component parameters
B.
a percent of the voltage division ratio squared
C.
total current squared multiplied by the resistor values
D.
a percent of the total power depending on resistor ratios
Answer: Option A
5. The current flowing through an unloaded voltage divider is called the: A.
resistor current
B.
load current
C.
bleeder current
D.
voltage current
2. What is the power dissipated by R2, R4, and R6?
Answer: Option C
6. When a Wheatstone bridge is in a balanced condition, the center voltmeter in the bridge will read: A.
P2 = 417 mW, P4 = 193 mW, P6 = 166 mW
B.
P2 = 407 mW, P4 = 183 mW, P6 = 156 mW
C.
P2 = 397 mW, P4 = 173 mW, P6 = 146 mW
D.
P2 = 387 mW, P4 = 163 mW, P6 = 136 mW
A.
twice the source voltage
B.
the same as the source voltage
C.
zero volts
D.
half the source voltage
Answer: Option C
Answer: Option A
7. When a load is connected to a voltage divider, the total resistance of the circuit will:
3.
A.
Decrease
B.
Double
C.
Increase
D.
remain the same
Answer: Option A
If the load in the given circit is 120 k loaded output voltage?
, what is the
8. With 21 V applied, if R1 = 5 ohms, R2 = 35 ohms, and R3 = 14 ohms, what is the current of R2 if R1 is series connected with parallel circuit R2 and R3? A.
200 mA
A.
4.21 V
B.
800 mA
B.
15.79 V
C.
600 mA
C.
16 V
D.
400 mA
D.
19.67 V Answer: Option D
Answer: Option B
4. In a series–parallel circuit, individual component power dissipations are calculated using:
9. What is the total resistance of a circuit when R1 (7 k ) is in series with a parallel combination of R2 (20 k ), R3 (36 k ), and R4 (45 k )?
A.
4k
B.
17 k
C.
41 k
D.
108 k
.
Answer: Option B
10.
A.
I2 = 4 mA, I3 = 2 mA
B.
I2 = 4.5 mA, I3 = 2.5 mA
C.
I2 = 5 mA, I3 = 3 mA
D.
I2 = 5.5 mA, I3 = 3.5 mA
Answer: Option C
13 .
If the load in the given circuit is 80 k the bleeder current? A.
196
B.
1.96 mA
C.
2 mA
D.
2.16 mA
, what is
A
Answer: Option B
11 .
If the load in the given circuit is open, what is the unloaded output voltage? A.
0V
B.
4V
C.
16 V
D.
20 V
Answer: Option C
1 What is the total resistance? 4 .
What is the total resistance of the given circuit? A.
92
A.
2.2 k
B.
288
B.
3.2 k
C.
17.7
C.
4.2 k
D.
128
D.
5.2 k
Answer: Option A
12 What are the branch currents I2 and I3?
Answer: Option B
15 .
A.
the same as the source voltage
B.
half the source voltage
C.
zero volts
D.
twice the source voltage
Answer: Option C
19. What is the voltage to the load?
How much voltage is dropped across R3 in the given circuit? A.
46 V
B.
34 V
C.
23 V
D.
12 V
Answer: Option D
1 When placed into a circuit, how are electronic 6 components usually connected? . A. positive terminal to positive terminal
A.
11.4 V
B.
12.4 V
C.
13.4 V
D.
15.4 V
Answer: Option D
B.
in parallel
C.
as a combination of series and parallel
D.
in series
20. The first goal to accomplish in analyzing a complex series-parallel circuit is to
Answer: Option C
17.
A.
equate all parallel components
B.
equate all series components
C.
solve for all the voltage drops
D.
solve for the total current and resistance
Answer: Option D
21 .
If the load in the given circuit is 12 k loaded output voltage? A.
5.88 V
B.
14.12 V
C.
16 V
D.
17.14 V
, what is the
Answer: Option B
18. If a Wheatstone bridge is balanced, a voltmeter in the center of the bridge will read:
Which circuit fault do the meter readings in the given figure indicate? A.
The 1 k
B.
The 4.7 k
resistor is open. resistor is open.
C.
The 2.2 k
resistor is open.
D.
The 3.3 k
resistor is open.
D.
90 ohms
Answer: Option C
Answer: Option B 26. Components or combinations of components with common currents, in a series–parallel circuit, are in:
22.
A.
parallel with each other
B.
series with each other
C.
either series or parallel with each other
D.
none of the above
Answer: Option C
27. What determines if resistor connections are in series, parallel, or series–parallel? How much current is flowing through R1 in the given circuit? A.
0.3 A
B.
0.15 A
C.
0.5 A
D.
0.68 A
Answer: Option C
A.
the voltage source
B.
the power source
C.
Resistance
D.
current flow
Answer: Option D
28 What is the total resistance? .
23. If R1 is in series with parallel connected to R2 and R3, what happens to total current if R2 opens? A.
Increases
B.
Decreases
C.
remains the same
D.
cannot tell
Answer: Option B
24. The first goal(s) to accomplish in analyzing a complex series–parallel circuit is to: A.
equate all parallel components
B.
equate all series components
C.
solve for all the voltage drops
D.
solve for the total current and resistance
Answer: Option D
25. If a series–parallel circuit has all 30-ohm resistors, what is the total resistance when R1 is in series with a parallel circuit consisting of R2 and R3? A.
10 ohms
B.
20 ohms
C.
45 ohms
A.
800
B.
1.2 k
C.
1.6 k
D.
1.8 k
Answer: Option D
29. If R1 is in series with a parallel combination of R2, R3, and R4, when the resistance value of R2 increases, the voltage across R3 will A.
Increase
B.
Decrease
C.
remain the same
D.
Cannot tell
Answer: Option A
30A Wheatstone bridge can be used to determine an unknown
.
A.
Current
B.
resistance
A.
220
C.
Power
D.
voltage
B.
6,899
C.
1,232
D.
More information is needed in order to find RUNK.
Answer: Option B 31 .
Answer: Option A
34. With 6 V applied, what is the voltage across R2 of a parallel combination of R2 (1 k ), R3 (2 k ), and R4 (1 k ) in series with R1, whose value is 2 k ?
Which circuit fault do the meter readings in the given figure indicate? A.
The 1 k
B.
The 4.7 k
resistor is shorted.
C.
The 2.2 k
resistor is shorted.
D.
The 3.3 k
resistor is shorted.
A.
1V
B.
3V
C.
5V
D.
6V
Answer: Option A
resistor is shorted. 35. What is the power dissipated by R1, R2, and R3?
Answer: Option D
32. In a series–parallel circuit consisting of R1 and R2 in series and connected in parallel with R3, if R1 opens, then R2's voltage will: A.
Increase
B.
Decrease
C.
remain the same
D.
cannot tell
Answer: Option B
33.
A.
P1 = 0.13 W, P2 = 0.26 W, P3 = 0.12 W
B.
P1 = 0.26 W, P2 = 0.52 W, P3 = 0.23 W
C.
P1 = 0.52 W, P2 = 0.92 W, P3 = 0.46 W
D.
P1 = 1.04 W, P2 = 1.84 W, P3 = 0.92 W
Answer: Option B
V - CAPACITORS 1. In a 20 Vac series RC circuit, if 20 V is measured across the resistor and 40 V is measured across the capacitor, the applied voltage is: A.
45 V
B.
50 V
C.
55 V
D.
60 V
Answer: Option A
2. Select the equation below that represents the relationship between charge, capacitance, and voltage for a capacitor. In the given circuit, what is RUNK equal to if RV must be adjusted to 1,232 in order to balance the bridge?
A.
Q = CV
B.
C = QV
C.
D.
V = IR
Answer: Option A
A.
4.7 ohms
B.
29.5 ohms
C.
34 ohms
D.
213 ohms
Answer: Option C
3. When is a capacitor fully charged? 7. What is the total capacitance? A.
when the voltage across its plates is of the voltage from ground to one of its plates
B.
when the current through the capacitor is the same as when the capacitor is discharged
C.
when the voltage across the plates is 0.707 of the input voltage
D.
when the current through the capacitor is directly proportional to the area of the plates
Answer: Option B
A.
1F
B.
12 F
C.
0.615 F
D.
8F
Answer: Option B
4.
8. What is this circuit?
What is the reactive power in the given circuit? A.
0 VAR
B.
691
C.
44.23 mVAR
D.
1.45 kVAR
VAR
Answer: Option C
5. What is the angle theta value for a 5.6 F capacitor and a 50-ohm resistor in series with a 1.1 kHz, 5 Vac source? A.
27.3 degrees
B.
62.7 degrees
C.
–27.3 degrees
D.
–62.7 degrees
A.
bandpass filter
B.
high-pass filter
C.
low-pass filter
D.
differentiator
Answer: Option B
9. After which time constant can a capacitor be considered to be fully charged? A.
first
B.
third
C.
fifth
D.
seventh
Answer: Option C Answer: Option C 6. When a 4.7 F capacitor is connected to a 1 kHz source, what is its capacitive reactance?
10. You could increase the time constant of an RC circuit by A.
adding a resistor in parallel with the circuit resistance
B.
adding a capacitor in parallel with the circuit capacitance
C.
increasing the amplitude of the input voltage
D.
exchanging the position of the resistor and capacitor in the circuit
Answer: Option B
11. A capacitor's rate of charge is considered: A.
magnetic
B.
a current block
C.
linear
D.
exponential
Answer: Option D
A.
4.57 mA
B.
9.327 mA
C.
11.570 mA
D.
13.830 mA
Answer: Option A
15. As a capacitor is being charged, current flowing into the capacitor will: A.
increase
B.
decrease
C.
remain the same
D.
cannot tell
Answer: Option B
16. What is the phase shift between the voltage across the resistor and the voltage from the source? 12. A resistor and an output capacitor form a series circuit with a square wave applied. The circuit is: A.
an integrator
B.
a differentiator
C.
a multiplier
D.
a divider
Answer: Option A
13. If an open capacitor is checked with an ohmmeter, the needle will: A.
stay on zero
B.
stay on infinity
C.
move from zero to infinity
D.
move from infinity to zero
Answer: Option B
14. What is the circuit's total current?
A.
VR leads VS by 17°
B.
VR leads VS by 73°
C.
VR lags VS by 73°
D.
VR lags VS by 17°
Answer: Option B
17. A capacitor stores energy within a dielectric between the conducting plates in the form of: A.
a magnetic field
B.
positive voltage
C.
negative voltage
D.
an electric field
Answer: Option D
18. As a capacitor is being charged, the voltage across its terminals will: A.
increase
B.
decrease
C.
remain the same
D.
oppose the source
23. In an ac circuit, an output capacitor and a resistor are connected in series with an ac signal. What filter action will be the result?
Answer: Option A
19. With a 500 kHz signal source, what would be the value of a capacitor yielding a capacitive reactance of 1 k ? A.
318 pF
B.
2 nF
C.
3.18
D.
2F
A.
bandpass
B.
low-pass
C.
high-pass
D.
band-stop
Answer: Option B
24. What is the total opposition to current in a series RC circuit called? F
A.
impedance
B.
inductance
C.
reactance
D.
resistance
Answer: Option A Answer: Option A 25. Which of the following statements is true? 20. After a capacitor has charged for 1 tc, what percentage of current remains in the resistor? A.
63.2
B.
36.8
C.
13.5
D.
5.0
Answer: Option B 21. If a current of 40 mA flows through a series circuit consisting of a 0.4 F capacitor and a resistor in series with a 4 kHz, 40 Vac source, what is the total circuit impedance? A.
10
B.
100
C.
1k
D.
1M
A.
The voltage to which a capacitor is charged can change instantaneously.
B.
The current in a capacitive circuit takes time to change.
C.
A fully charged capacitor appears as a short to dc current.
D.
An uncharged capacitor appears as a short to an instantaneous change in current.
Answer: Option D
26. In a capacitive circuit, current flow is limited to
Answer: Option C
22.
A.
charging periods
B.
discharging periods
C.
neither charging periods nor discharging periods
D.
both charging periods and discharging periods
Answer: Option D
27 What circuit has the following frequency response? .
What is the capacitance of the circuit shown in the given circuit? A.
0.066
B.
0.9
C.
65.97 pF
A.
bandpass filter
D.
900 pF
B.
high-pass filter
C.
low-pass filter
F F
Answer: Option A
D.
integrator
Answer: Option B
Answer: Option C 33. What is the reactance value for a capacitor installed in a dc circuit? 28. A capacitor is constructed of two parallel: A.
conductors
B.
semiconductors
C.
inductors
D.
dielectrics
Answer: Option A
Plate area, dielectric strength, and plate separation
B.
Voltage rating, dielectric constant, and temperature coefficient
C.
Temperature coefficient, plate area, and plate separation
D.
Plate area, dielectric constant, and plate separation
A.
electrolytic
B.
plastic film
C.
oxide casing
D.
waxed paper
B.
moderate
C.
infinite
D.
cannot tell
34. In a purely capacitive circuit, A.
current leads voltage by 90°
B.
voltage leads current by 90°
C.
current lags voltage by 90°
D.
current and voltage have a phase relationship of 0°
Answer: Option A
Answer: Option D
30. Most older types of paper capacitors have been replaced by which type of construction?
zero
Answer: Option C
29. Which of the following determines the capacitance of a capacitor? A.
A.
3 5.
Answer: Option B
31. If C1, a 4.7 F capacitor, and C2, a 3.3 F capacitor are in series with 18 Vdc applied, what is the voltage across C1?
How long would it take the capacitor in the given circuit to completely discharge if the switch was in position 2?
A.
3.3 V
A.
22 ms
B.
7.4 V
B.
69 ms
C.
6.6 V
C.
345 ms
D.
9.4 V
D.
420 ms
Answer: Option B
32. What is the impedance of a series RC circuit that consists of a 0.22 F capacitor and a 200-ohm resistor connected to a 3 kHz source?
Answer: Option D
36. What is the capacitive reactance if I = 1 amp, V = 2 volts, C = 5 F, and frequency = 10 Hz? A.
0.2
A.
214 ohms
B.
0.5
B.
313 ohms
C.
0.02
C.
414 ohms
D.
0.003
D.
880 ohms Answer: Option D
37. What is wrong with a leaky capacitor? A.
It is open.
B.
It is shorted.
C.
The dielectric resistance has increased.
D.
The dielectric resistance has decreased.
Answer: Option D
A.
294 ps
B.
13.5 ms
C.
21.25 ms
D.
2.16 Gs
38. What is the value of a capacitor labeled 102? A.
10,000 pF
B.
1000 pF
C.
1000
D.
10,000
Answer: Option C
F F
Answer: Option B
39. If the dielectric constant of a capacitor is decreased, then its capacitance will: A.
increase
B.
decrease
C.
remain the same
D.
be destroyed
Answer: Option B
40. What is the dielectric constant for ceramic? A.
between 6 and 8000
B.
5.0
C.
between 5 and 1000
D.
3000
Answer: Option A
41. What is the voltage across a capacitor after being charged from a 100 V source for a period of one time constant? A.
37.8 V
B.
38 V
C.
63 V
D.
101 V
Answer: Option C
42. What is the dc charging/discharging time constant for the circuit?
43. Power stored from the source and then returned to the source is called: A.
apparent power
B.
impedance power
C.
reactive power
D.
true power
Answer: Option C
44. Capacitor value markings are usually: A.
alphanumeric
B.
color dabs
C.
standard
D.
white print
Answer: Option A
45 A source voltage across a capacitor will: . A. lead the current by 90 degrees B.
lead the current by 180 degrees
C.
lag the current by 90 degrees
D.
lag the current by 180 degrees
Answer: Option C
46 .
50. Which material has the highest dielectric strength? A.
Air
B.
Paper
C.
Mica
D.
Oil
Answer: Option C
51. What is the circuit's impedance?
How long would it take the capacitor in the given circuit to completely charge if the switch was in position 1? A.
22 ms
B.
69 ms
C.
345 ms
D.
440 ms
Answer: Option C
47. An 8 V power source is charging a capacitor. How many volts will be across the capacitor at the second time constant? A.
1 volt
B.
3 volts
C.
5 volts
D.
7 volts
Answer: Option D
48. The material used between the plates of a capacitor is called its: A.
insulation material
B.
dielectric material
C.
separation material
D.
plate-divider material
A.
1192
B.
843
C.
723
D.
511
Answer: Option A
52. In an ac circuit, a capacitor and an output resistor are connected in series with an ac signal. What filter action will be the result? A.
bandpass
B.
low-pass
C.
high-pass
D.
band-stop
Answer: Option C
53. What is the impedance of this circuit?
Answer: Option B
49. When a circuit consists of a capacitor and a resistor in series with a voltage source, and the voltage across the resistor is zero, then the capacitor is: A.
charging
B.
discharging
C.
fully charged
D.
fully discharged
Answer: Option C
A.
2098
B.
2000
C.
1902
D.
will:
1798
Answer: Option A
54. What is the reactive power?
A.
immediately discharge
B.
recharge
C.
remain charged
D.
leak the charge
Answer: Option D
59. What is the total current for a 5 MHz, 1 Vac circuit that consists of a 27 pF capacitor and a 1 k resistor connected in parallel?
A.
6.8 mW
B.
9.8 mW
C.
12.8 mW
D.
15.8 mW
A.
459
A
B.
647
A
C.
1.31 mA
D.
1.85 mA
Answer: Option C
60. What is the value of a capacitor that can store two coulombs of charge when 500 volts is applied across its plates?
Answer: Option B
55. A practical capacitor A.
is a short to dc
B.
looks like a capacitor in parallel with a resistor
C.
is an open to ac
D.
stores energy in a magnetic field
Answer: Option B
56. Which of the following is the reference vector for parallel RC circuits? A.
R
B.
I
C.
C
D.
V
A.
4
B.
250
C.
4,000
D.
250 F
F F F
Answer: Option C
61. The strength of an electric field at a given point is proportional to the potential difference on the plates and inversely proportional to the: A.
plate separation
B.
negative plate only
C.
field strength
D.
charge difference
Answer: Option A
Answer: Option D
57. What do variable capacitors use for dielectric? A.
ceramic, electrolytic, mica, or paper
B.
air, ceramic, mica, or plastic
C.
ceramic, paper, plastic, or mica
D.
mica, ceramic, plastic, or electrolytic
Answer: Option B
58. If a charged capacitor is disconnected from a circuit, it
62. How is ac current related to ac voltage in a purely capacitive circuit? A.
AC current is 0.707 of the ac voltage.
B.
AC current lags ac voltage.
C.
AC current is 0.637 of the ac voltage.
D.
AC current leads ac voltage.
Answer: Option D
63. What is the voltage across the capacitor?
A.
an increase in total XC
B.
a decrease in total XC
C.
no change in total XC
D.
total opposition to voltage in the circuit
Answer: Option A
68. The quantity that represents an ideal capacitor dissipating 0 W of power is A.
instantaneous power
A.
7.07 V
B.
true power
B.
1.11 V
C.
reactive power
C.
111 mV
D.
resistive power
D.
7.07 mV
Answer: Option B
Answer: Option C 69. If a capacitor is placed across a 20 V source, what will be the amount of charge after 5 tc? 64. For a given charge difference, electrostatic field strength varies according to:
A.
5.0 V
A.
plate differential
B.
12.8 V
B.
plate area
C.
13.5 V
C.
plate distance
D.
20 V
D.
dielectric quantity
Answer: Option D
Answer: Option B
65. A capacitor has 25 V across its plates and a stored charge of 1500 value? A.
60 pF
B.
60
C.
16.67 mF
D.
37.5 mF
C. What is the capacitance
F
Answer: Option B
66.
A capacitor and an output resistor form a series circuit with a square wave applied. The circuit is: A.
an integrator
B.
a differentiator
C.
a multiplier
D.
a divider
70. What is the impedance of an ac RC parallel circuit if the resistance is 12 ohms and the capacitive reactance equals 5 ohms? A.
0.2 ohms
B.
3.5 ohms
C.
4.6 ohms
D.
13 ohms
Answer: Option C
71. What will a 1
F capacitor store?
A.
one coulomb of charge
B.
6.24 x 1012 electrons
C.
one volt
D.
one
A of current
Answer: Option B
72. In an RC circuit, true power (PR) equals: Answer: Option B A. 67. Capacitive reactance values connected in series offer
B.
VS × I
C.
I2R
D.
VT × R T
Answer: Option C
73. What is the power factor if the apparent power of a circuit is 5 W, while the true power is 4 W? A.
0.0 W
B.
0.8 W
C.
1.0 W
D.
1.25 W
Answer: Option B
74. If the reactive power of a circuit is 50 mW while the apparent power is 64 mW, then what is the true power of the circuit? A.
14 mW
B.
36 mW
C.
40 mW
D.
114 mW
across R3 25 A.
2.88 V
B.
5.9 V
C.
8.34 V
D.
14 V
s after the switch is moved to position 2?
Answer: Option B
3. The electrical energy consumed by a coil is stored in the form of: A.
an electrical field
B.
a force field
C.
an electrostatic field
D.
a magnetic field
Answer: Option D
4. What is magnetic flux? A.
the number of lines of force in webers
B.
the number of lines of force in maxwells
C.
the number of lines of force in teslas
D.
the number of lines of force in flux density
Answer: Option C Answer: Option A
VI – INDUCTORS 1. Electricity may be generated by a wire: A.
carrying current
B.
wrapped as a coil
C.
that has neutral domains
D.
passing through a flux field
Answer: Option D
2.
5. As current travels within a conductor: A.
the magnetic field aids the current
B.
a magnetic field is developed around it
C.
the wire tries to point north
D.
an electrostatic field opposes the current
Answer: Option B
6. What type of device consists of a coil with a moveable iron core? A.
solenoid
B.
reed switch
C.
relay
D.
armature
Answer: Option A
7. What is hysteresis?
In the given circuit, what will the voltage be
A.
lead between cause and effect
B.
lag between cause and effect
C.
lead between voltage and current
D.
lag between voltage and current
Answer: Option B
8. In a purely inductive circuit, A.
current leads voltage by 90°
B.
voltage lags current by 90°
C.
voltage leads current by 90°
D.
voltage and current are in phase (0°)
Answer: Option C
9. A series RL filter circuit with an output across the inductor will result in what type of filtering? A.
passing of the higher frequencies
B.
passing of the lower frequencies
C.
blocking of the higher frequencies
D.
blocking of a certain range of frequencies
Answer: Option A
10.
A.
direction of the induced voltage produces an opposition
B.
direction of an induced current produces an aiding effect
C.
emf depends on the rate of cutting flux
D.
emf is related to the direction of the current
Answer: Option C
13. A henry value divided by a circuit resistive value provides the: A.
counter emf value
B.
induced voltage amplitude
C.
rise or decay time constant
D.
quality factor of the coil
Answer: Option B
14. What does Faraday's law concern? A.
a magnetic field in a coil
B.
a magnetic field cutting a conductor
C.
a magnetic field hystersis
D.
a magnetic field in a conductor
Answer: Option B
What is the total inductance in the given circuit?
15. The polarity of induced voltage while a field is collapsing is:
A.
160 mH
A.
independent of the force creating it
B.
300 mH
B.
opposite to the force creating it
C.
900 mH
C.
identical to the force creating the field
D.
1700 mH
D.
present only if the force is stationary
Answer: Option A
11. On a schematic, dashed lines between two vertical coils usually mean the transformer has: A.
an air core
B.
an iron core
C.
a nonmetallic core
D.
a ferrite core
Answer: Option D
Answer: Option B
16. What is the permeability of transformer iron? A.
50
B.
450
C.
1,500
D.
5,500
Answer: Option D
17. Electromagnetism is the: A.
magnetic field caused by a permanent magnet
B.
action between a permanent and an artificial magnet
C.
magnetic field action with a current-carrying wire
D.
current in the coil
12. Faraday's law states that the:
Answer: Option C
18. A magnetic field has: A.
polar fields
B.
lines of force
C.
magnetomotive force
D.
lines of reluctance
Answer: Option B
19. Which two values are plotted on a B-H curve graph? A.
reluctance and flux density
B.
permeability and reluctance
C.
magnetizing force and permeability
D.
flux density and magnetizing force
Answer: Option D
20. What is the number of turns required in the secondary winding for a transformer when 120 volts is applied to a 2400-turn primary to produce 7.5 Vac at the secondary? A.
75 turns
B.
150 turns
C.
900 turns
D.
1920 turns
Answer: Option B
21. The four factors determining inductance are the number of turns, coil length, coil area, and: A.
Permeability
B.
Reluctance
C.
counter emf
D.
coefficient of coupling
Answer: Option A
22. What is the inductive reactance if the Q of a coil is 60, and the winding resistance is 5 ? A.
0.083
B.
12
C.
30
D.
300
Answer: Option D
23. The time difference, or lag, between flux density and magnetizing force is known as: A.
eddy current
B.
magnetic saturation
C.
Hysteresis
D.
Coercivity
Answer: Option C
24. A magnetic circuit breaker will open to protect equipment only when: A.
voltage is exceeded
B.
an open is in the equipment
C.
the equipment is operating properly
D.
current is exceeded
Answer: Option D
25. Electromagnetic induction is the generation of: A.
electricity from magnetism
B.
electricity from electricity
C.
magnetism from electricity
D.
magnetism from magnetism
Answer: Option A
26. Inductance is: A.
directly proportional to the length of the coil
B.
directly proportional to the number of turns on the coil
C.
inversely proportional to the cross-sectional area of the coil
D.
inversely proportional to the permeability
Answer: Option B
27. Current will cause a magnetic field in a conductor as follows: A.
An ac current causes a fixed polarity magnetic field.
B.
A dc current causes a fixed polarity magnetic field.
C.
A dc current causes an alternating magnetic field.
D.
An ac current causes a fixed polarity magnetic field and a dc current causes an alternating magnetic field.
Answer: Option B
28. What is the total inductance, assuming no mutual inductance?
connected to a middle loop that is not an end connector, it is called a: A.
multiple-tapped secondary
B.
center-tapped secondary
C.
multiple winding secondary
D.
single winding secondary
Answer: Option B
32.
A.
12 mH
B.
6 mH
C.
0.73 mH
D.
0 mH
Answer: Option A
29. During a current change, the ability of a conductor to produce counter emf within itself is called:
A 24 V peak source is connected across a 900 H inductor. If the frequency of the source is 22 kHz, what is the reactive power? A.
2.3 VAR
B.
4.6 VAR
C.
9.3 VAR
D.
0 VAR
Answer: Option A
A.
back emf
B.
self-induction
A.
1.1 x 10−4
C.
a henry
B.
5.65 x 10−4
D.
impedance
C.
6.9 x 10−3
D.
8.8 x 10−3
33. What is the permeability of machine steel?
Answer: Option B Answer: Option B 30 .
34. What will happen when an inductor's magnetic field collapses? A.
Current will double.
B.
Voltage will be induced.
C.
A new field will expand.
D.
Counter emf will be high.
Answer: Option B
If the switch is moved to position 1 in the given circuit, how long will it take for the current to reach its maximum value? A.
72.5
B.
532
s
C.
610
s
D.
833
s
s
Answer: Option B
31. When a transformer secondary lead has been
35. With a square wave input, an RL differentiator circuit with an output across the inductor will produce what type of waveform? A.
dc
B.
short time-duration pulses
C.
exponential-shaped pulses
D.
only a phase shift
Answer: Option B
36. How long until the current is at a maximum?
Answer: Option D
40. What term is used to describe the action of magnetic flux from one circuit that cuts across the conductors of another circuit?
A.
0
s
B.
5
s
C.
15
s
D.
25
s
A.
self-inductance
B.
rectification
C.
mutual inductance
D.
magnetism
Answer: Option C
37. Find VR and VL.
41. Reactance in an inductive circuit will: A.
increase with frequency
B.
decrease with frequency
C.
be independent from frequency
D.
depend on the value of XC
Answer: Option A
42. A turns ratio of 5 for a transformer implies:
A.
VR = 41.6 V, VL = 78.4 V
B.
VR = 48 V, VL = 110 V
C.
VR = 56 V, VL = 106 V
D.
VR = 60 V, VL = 60 V
Answer: Option C
38. If 360 Vac is the output of a 300-turn secondary winding, what is the input voltage when the primary winding has 150 turns? A.
2.4 Vac
B.
150 Vac
C.
180 Vac
D.
720 Vac
Answer: Option C
39. When a magnet enters a coil and a voltage is induced, the process is known as: A.
an alternation
B.
self-inductance
C.
counter emf
D.
flux linkage
A.
more primary turns than secondary turns
B.
more secondary current than primary current
C.
larger source impedance than load impedance
D.
more secondary turns than primary turns
Answer: Option D
43. A practical inductor A.
has inductance
B.
has winding resistance
C.
has winding capacitance
D.
all of the above
Answer: Option D
44. When current in an inductor starts to change, it cannot react instantly due to: A.
fixed coil resistance
B.
eddy current generation
C.
applied emf of the circuit
D.
the counter emf of the coil
Answer: Option D
45. What is the approximate time for a complete decay of
400 mA of inductor current, when R = 10 ohms and L = 20 H?
A.
number of turns
A.
10 seconds
B.
permeability of the core
B.
8 seconds
C.
spacing between turns
C.
4 seconds
D.
area of the coil
D.
2 seconds
Answer: Option C
Answer: Option A 51. The output phase for a transformer is: 46. A utility pole transformer used to supply a residential customer with two phases uses: A.
two phases on the primary
B.
a center tap on the secondary
C.
a separate ground for each phase
D.
a small coefficient of coupling
Answer: Option B
47. What is the inductive reactance?
A.
5.2
B.
7.5
C.
1.3 k
D.
7.5 k
Answer: Option D
48. When a coil collapses the induced circuit current will: A.
be in the same direction
B.
go to zero
C.
aid counter emf buildup
D.
be in the opposite direction
A.
in phase with the input
B.
out of phase with the input
C.
dependent on the direction of the primary and secondary windings
D.
dependent on the frequency of the primary source
Answer: Option C
52. Opposition to current flow without the dissipation of energy is called: A.
resistance
B.
inductive reactance
C.
counter emf
D.
impedance
Answer: Option B
53. With 100 Vac applied to the primary of a transformer so that it draws 500 mA, what will be the 300 Vac secondary current? A.
1500 mA
B.
200 mA
C.
167 mA
D.
150 mA
Answer: Option C Answer: Option A
49. When a rate of one ampere per second causes an induced voltage of one volt, the unit of measure is A.
a lenz
B.
an ohm
C.
a farad
D.
a henry
Answer: Option D
50. If you wanted to decrease the inductance of a coil, you might increase the:
54. Which coil would be used as a step-up transformer primary if coil number 1 has 100 more turns than coil number 2? A.
The coil windings must be the same.
B.
coil 1
C.
The coil ratio is too small.
D.
coil 2
Answer: Option D
55. Find IR and IL.
B.
33.3 mH
C.
98.0 mH
D.
150.0 mH
Answer: Option C
A.
IR = 50 mA, IL = 109 mA
B.
IR = 150 mA, IL = 9 mA
C.
IR = 50 mA, IL = 151 mA
D.
IR = 150 mA, IL = 53 mA
.
59. A transformer is used: A.
to couple electric energy from one dc circuit to another
B.
to couple electric energy from an ac circuit to a dc circuit
C.
to couple electric energy from a dc circuit to an ac circuit
D.
to couple electric energy from one ac circuit to another
Answer: Option D
.
56.
When the transformer secondary is not loaded: A.
secondary voltage increases
B.
no secondary current flows
C.
no secondary voltage is present
D.
secondary current increases
Answer: Option B 57. What is the current rise after 2 time constants if Vs = 12 V dc, R = 60 , and the inductor is rated at 24 mH? A.
79.9 mA
B.
126.4 mA
C.
173.0 mA
D.
198.6 mA
Answer: Option D
.
60. Which of the following is NOT one of the three major types of fixed inductor? A.
air core
B.
ferrite core
C.
magnesium core
D.
iron core
Answer: Option C Answer: Option C
. .
58. What is the total inductance of a 5 H and a 100 mH coil connected in parallel? A.
4.76 mH
61. What is the impedance of a 1 kHz series RL circuit when R and XL are both 1000 ohms? A.
500 ohms
B.
1000 ohms
C.
1414 ohms
D.
2000 ohms
65. Indication of transformer primary and secondary voltage relationships is accomplished by:
Answer: Option C
A.
color-coded wires
B.
dot notation
C.
black, rather than gray, casings
D.
winding ratios
. Answer: Option B
.
62. What is remanence? A.
reactance
B.
reluctance
C.
retentitivity
D.
resistance
Answer: Option C
66. As a generator armature passes the 270 degree point, the induced voltage is:
.
63. When an electromagnet reaches maximum strength, it is considered to be:
64.
A.
in field condition
B.
at saturation
C.
inhibited
D.
at field strength
Answer: Option B You could decrease the time constant of an RL circuit by A.
adding a resistor in parallel with the circuit resistance
B.
adding an inductor in series with the circuit inductance
C.
decreasing the amplitude of the input voltage
D.
exchanging the position of the resistor and inductor in the circuit
Answer: Option B
.
A.
at maximum negative
B.
between maximum negative and zero
C.
at maximum positive
D.
between zero and maximum positive
Answer: Option A
.
67. A value of "ten to the eighth power magnetic lines of force" is for the term: A.
field
B.
flux
C.
coulomb
D.
weber
Answer: Option D
.
68. A change of one ampere per second in an inductor that induces a voltage of one volt is considered as which unit value? A.
a lenz
B.
an ohm
C.
a farad
D.
a henry
Answer: Option D
B.
placed in parallel with the load and aids any current changes
C.
placed in parallel with the load and opposes any current changes
D.
placed in series with the load and opposes any current changes
. Answer: Option D
69. What is the name of the part inside a relay that is moved by the action of the electromagnet? A.
armature
B.
conductor
C.
contacts
D.
solenoid
Answer: Option A
.
73. A loaded transformer will achieve mutual induction when:
.
A.
secondary current increase causes a primary current decrease
B.
primary current is increased by an increase in secondary current
C.
primary current is decreased by an increase in secondary current
D.
secondary current decrease causes a primary current increase
70. If the primary of a 4:1 turns transformer dissipates 5 W, what is the secondary power? A.
5.0 W
B.
1.25 pW
C.
9.5 W
D.
20.0 mW
Answer: Option B
.
Answer: Option A 71. The unit of flux density is: 74. Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms?
A.
magnetomotive force
B.
a weber
A.
1.38:1
B.
1.67:1
C.
a maxwell
C.
0.72:1
D.
0.60:1
D.
a tesla Answer: Option D
Answer: Option D
. tesla or weber/m2 is the unit of flux density
75. A transformer will have: 72. When used as a filter, an inductor is A.
placed in series with the load and aids any current changes
A.
primary and secondary windings
B.
primary and secondary current
C.
primary wattage producing secondary current
D.
different frequencies for the primary and secondary
A.
placed in series with the load and aids any current changes
B.
placed in parallel with the load and aids any current changes
C.
placed in parallel with the load and opposes any current changes
D.
placed in series with the load and opposes any current changes
Answer: Option A
.
Answer: Option D 76. What is the phase angle of a 24 Vac parallel RL circuit when R = 45 ohms and XL = 1100 ohms? A.
0.001 degrees
B.
2.300 degrees
C.
87.600 degrees
D.
89.900 degrees
.
73. A loaded transformer will achieve mutual induction when:
Answer: Option B
.
A.
secondary current increase causes a primary current decrease
B.
primary current is increased by an increase in secondary current
C.
primary current is decreased by an increase in secondary current
D.
secondary current decrease causes a primary current increase
77. A winding of wire can be called A.
an inductor
B.
a coil
C.
a choke
D.
All of the above
Answer: Option D 71. The unit of flux density is: A.
magnetomotive force
B.
a weber
C.
a maxwell
D.
a tesla
Answer: Option B
.
74. Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms? A.
1.38:1
B.
1.67:1
C.
0.72:1
D.
0.60:1
Answer: Option D Answer: Option D . tesla or weber/m2 is the unit of flux density
75. A transformer will have: A. 72. When used as a filter, an inductor is
primary and secondary windings
B.
primary and secondary current
C.
primary wattage producing secondary current
D.
different frequencies for the primary and secondary
79. Fixed transformers have:
Answer: Option A
A.
a center-tapped secondary
B.
multiple windings
C.
turns ratios that cannot be changed
D.
a multiple-tapped secondary
. Answer: Option C
76. What is the phase angle of a 24 Vac parallel RL circuit when R = 45 ohms and XL = 1100 ohms? A.
0.001 degrees
B.
2.300 degrees
C.
87.600 degrees
D.
89.900 degrees
.
80. In a B-H curve, magnetizing force is equal to: A.
Answer: Option B
B.
H=I×N
C.
ampere-turns per weber
D.
webers per square meter
. Answer: Option A
77. A winding of wire can be called A.
an inductor
B.
a coil
C.
a choke
D.
All of the above
.
81. Which of the following represents a true equivalent of an inductor?
Answer: Option D 78. What happens when moving expanding lines of force encounter a conductor? A.
Current increases.
B.
Voltage is induced.
C.
Resistance is reduced.
D.
Power is increased.
A.
An inductance in series with a resistance and a capacitance
B.
A capacitance in parallel with the series combination of a resistance and an inductance
C.
An inductance in parallel with the series combination of a resistance and a capacitance
D.
The only quality a real inductor has is inductance.
Answer: Option B Answer: Option B
. .
82. In a transformer, what will happen to the primary current if the secondary magnetic field increases? A.
Ip will increase.
B.
Ip will be canceled.
C.
Ip will remain the same.
D.
Ip will decrease.
B.
0.69 mH
C.
12 mH
D.
24 mH
Answer: Option B
. Answer: Option A
.
86. A voltage is induced in a transformer secondary winding by the action of the:
83. The time required for one weber of flux to cut a conductor and produce one volt is: A.
one revolution
B.
one second
C.
one millisecond
D.
four revolutions
A.
secondary magnetic field
B.
primary turns ratio
C.
primary magnetic field
D.
secondary counter emf
Answer: Option C
. Answer: Option B
.
87. What is electromagnetism?
84. What is the maximum source current for a transformer rated at 10 kVA, 1000/500 60 Hz? A.
2A
B.
5A
C.
10 A
D.
20 A
Answer: Option D 85. What is the total inductance assuming no mutual inductance?
A.
the magnetic field generated around a conductor when a current passes through it
B.
the magnetic field generated in a conductor by an external voltage
C.
the voltage caused by a magnetic field in a conductor
D.
the current generated by an external magnetic field
Answer: Option A
.
88. Counter emf or induced voltage is:
A.
0 mH
A.
inversely proportional to the change in current
B.
directly proportional to the change in time
C.
directly proportional to the inductance in
D.
henrys
B.
9.0 degrees
inversely proportional to the inductance in henrys
C.
61.0 degrees
D.
81.0 degrees
Answer: Option C Answer: Option D 92. When a load is not connected to the secondary of a transformer:
.
89. What are the properties that determine the inductance of a coil? A.
Length of wire, number of turns, type of core material, length of core
B.
Number of turns, type of wire, length of core, and cross-sectional area of core
C. D.
Type of core material, number of turns, crosssectional area of core, and length of core Type of core material, type of wire, number of turns, and cross-sectional area of core
A.
primary current is zero
B.
primary current is inversely proportional to primary impedance
C.
secondary voltage is zero
D.
secondary voltage is proportional to primary impedance
Answer: Option B VII - RLC Circuits and Resonance 1. What is the applied voltage for a series RLC circuit when IT = 3 mA, VL = 30 V, VC = 18 V, and R = 1000 ohms?
Answer: Option C
A.
3.00 V
B.
12.37 V
C.
34.98 V
D.
48.00 V
. Answer: Option B
90. An inductor is in series with a voltage source, an open switch, and a resistor. The instant the switch is closed, the inductor acts like A.
a short
B.
an open
C.
a resistor
D.
a voltage source
.
2. What is the bandwidth of the circuit?
Answer: Option B
.
91. What is the phase angle between the source voltage and current, when a 100 mH inductor with a reactance of 6 k , and a 1 k resistor are in series with a source? A.
0.1 degrees
A.
31.8 Hz
B.
32.3 Hz
C.
142 Hz
D.
7.2 kHz
D.
149,970 Hz to 150,030 Hz
Answer: Option A Answer: Option B . .
3. In a parallel RLC circuit, which value may always be used as a vector reference? A.
current
B.
reactance
C.
resistance
D.
voltage
7. What is the quality factor?
Answer: Option D
.
4. How much current will flow in a 100 Hz series RLC circuit if VS = 20 V, RT = 66 ohms, and XT = 47 ohms? A.
1.05 A
B.
303 mA
C.
247 mA
D.
107 mA
A.
999
B.
223
C.
2.2
D.
0.99
Answer: Option C
.
Answer: Option C
8. What effect will a parallel tank have upon final filter current?
.
5. What is the Q (Quality factor) of a series circuit that resonates at 6 kHz, has equal reactance of 4 kilo-ohms each, and a resistor value of 50 ohms? A.
0.001
B.
50
C.
80
D.
4.0
Answer: Option C 6. What is the range between f1 and f2 of an RLC circuit that resonates at 150 kHz and has a Q of 30? A.
100.0 kHz to 155.0 kHz
B.
147.5 kHz to 152.5 kHz
C.
4500 kHz to 295.5 kHz
A.
very little
B.
The bandpass frequencies will change.
C.
The frequency cutoff will change.
D.
The impedance will block output.
Answer: Option A
.
9. What is the total current?
12. Series RLC voltage or impedance totals must be calculated by:
A.
56.6 mA
B.
141 mA
C.
191 mA
D.
244 mA
A.
subtracting the values
B.
graphing the angles
C.
adding vectors
D.
multiplying the values
Answer: Option C
.
Answer: Option B
13. What is the total current? .
10. When a parallel circuit resonates it is said to:
11.
A.
flywheel
B.
oscillate
C.
both of the above
D.
none of the above
Answer: Option C
A.
15.6 mA
B.
17.8 mA
C.
21.9 mA
D.
26.0 mA
Answer: Option A What is the resonant frequency in the given circuit? A.
11.6 Hz
B.
275.8 Hz
C.
1.5 kHz
D.
3.2 kHz
.
14. When XC = XL the circuit: Answer: Option D
.
A.
draws maximum current
B.
applied voltage is zero
C.
is at resonance
D.
draws minimum current
18 .
Answer: Option C
.
15.
How much current will flow in a series RLC circuit when VT = 100 V, XL = 160 , XC = 80 , and R = 60 ? A.
1A
B.
1 mA
C.
6.28 A
D.
10 A
What is the voltage across the capacitor in the given circuit?
Answer: Option A 16. When a full band of frequencies is allowed to pass through a filter circuit to the output, the resonant circuit is called a: A.
low-pass filter
B.
high-pass filter
C.
band-stop filter
D.
bandpass filter
A.
6.8 V
B.
11.9 V
C.
16.1 V
D.
22.9 V
Answer: Option D
.
1 9.
Answer: Option D
.
What is the impedance of the circuit in the given circuit? 17. At resonance, the term bandwidth includes all frequencies that allow what percentage of maximum current to flow? A.
50
B.
62.3
C.
70.7
D.
95.3
Answer: Option C
.
A.
1.05 k
B.
1.33 k
C.
2.19 k
D.
3.39 k
Answer: Option A
.
20. In a series RLC circuit the current can be found using:
Answer: Option C A.
.
B.
C.
both of the above
D.
none of the above
24. What is the resonance frequency?
Answer: Option C 2 What is the true power consumed in a 30 V series 1. RLC circuit if Z = 20 ohms and R = 10 ohms? A.
15.0 watts
B.
22.5 watts
C.
30.0 watts
D.
45.0 watts
Answer: Option B
.
A.
31.8 Hz
B.
71 Hz
C.
7.1 kHz
D.
31.8 kHz
Answer: Option B 22. What is the current phase angle for a parallel RLC circuit when IL = 15.3 A, IC = 0.43 A, and IR = 3.5 A? A.
76.7 degrees
B.
–4.25 degrees
C.
88.8 degrees
D.
–76.7 degrees
.
25. What is the range between f1 and f2 of an RLC circuit that resonates at 150 kHz and has a Q of 30? Answer: Option D
.
A.
100.0 kHz to 155.0 kHz
B.
147.5 kHz to 152.5 kHz
C.
4500 kHz to 295.5 kHz
D.
149,970 Hz to 150,030 Hz
Answer: Option B 23. At any resonant frequency, what voltage is measured across the two series reactive components? A.
applied
B.
reactive
C.
zero
D.
inductive and capacitive
26. .
29. Series RLC impedance or voltage totals must always be calculated by
What is the bandwidth in the given circuit. If the winding resistance of the coil is 12 ? A.
6.4 kHz
B.
47.2 kHz
C.
53.7 kHz
D.
60.2 kHz
A.
adding values vectorially
B.
graphing the angles
C.
multiplying the values
D.
subtracting the values
Answer: Option A
. Answer: Option A
30 .
.
27. At any resonant frequency, what net voltage is measured across the two series reactive components? A.
Applied voltage
B.
Reactive voltage
C.
Zero voltage
A.
3.5 mA
D.
VL + VC voltage
B.
5.5 mA
C.
9 mA
D.
11.4 mA
Answer: Option C
What is the current through the capacitor in the given circuit?
Answer: Option A 31What is the total impedance of a 60 Hz series RLC circuit . when XL = 7.5 ohms, XC = –265.3 ohms, and R = 33 ohms?
.
28. If the bandwidth of a filter increases:
A.
257.8 ohms
B.
259.9 ohms
A.
Q decreases
C.
290.8 ohms
B.
the roll-off rate increases
D.
1989.75 ohms
C.
the half-power frequency decreases
D.
the center frequency decreases
Answer: Option A
Answer: Option B
. Answer: Option B
32.
.
35. What is the impedance of the circuit?
What is the total current for the nonideal circuit in the given circuit. If it is at resonance? A.
0A
B.
284
C.
3.3 mA
D.
38.5 mA
A
Answer: Option B
.
33. What is the high cutoff frequency for an RLC circuit that resonates at 2000 Hz and has a bandwidth of 250 Hz? A.
2125 Hz
B.
2250 Hz
C.
1750 Hz
D.
8.0 Hz
36.
A.
12.2 k
B.
14.5 k
C.
17.8 k
D.
20.3 k
Answer: Option D
Answer: Option A
What is the resonant frequency in the given circuit?
.
34. Current in a series RLC circuit may always be used as: A.
a leading vector
B.
a reference
C.
an angle
D.
a lagging vector
A.
6.5 kHz
B.
53.7 kHz
C.
107.4 kHz
D.
18.1 MHz
Answer: Option B
.
D.
The larger of the two reactances is dominant.
Answer: Option D 37. .
40. What is the band pass (F1 – F2) of an RLC filter that resonates at 150 kHz and has a coil Q of 30?
What is the impedance of the circuit in the given circuit? A.
125.7
B.
297.6
C.
370.1
D.
423.3
A.
100.0 kHz to 155.0 kHz
B.
147.5 kHz to 152.5 kHz
C.
295.5 kHz to 4500 kHz
D.
149,970 Hz to 150,030 Hz
Answer: Option B 41. What is the power factor?
Answer: Option C
.
A.
0.279
B.
0.479
C.
0.679
D.
0.879
38. What is the approximate phase angle in a series RLC circuit when VC = 117 V, VR = 14.5 V, and VL = 3.3 V? A.
–45.0 degrees
B.
–82.7 degrees
C.
–90.0 degrees
D.
–172.7 degrees
Answer: Option B
.
Answer: Option B 42. What is the phase angle? .
39. Which statement best describes reactance in a series RLC circuit? A.
Capacitive reactance is always dominant.
A.
61.4º
B.
28.5º
B.
Inductive reactance is always dominant.
C.
-28.5º
D.
-61.4º
C.
Resistance is always dominant.
Answer: Option C
Answer: Option B What is the voltage across R1, C1, and L1?
.
43. What would be the power factor for an RLC circuit that acts inductively? A.
+90 degrees leading
B.
one
C.
zero
D.
–90 degrees lagging
Answer: Option C
A.
VR = 156 V, VC = 165 V, VL = 441 V
B.
VR = 178 V, VC = 187 V, VL = 503 V
C.
VR = 219 V, VC = 232 V, VL = 619 V
D.
VR = 260 V, VC = 276 V, VL = 735 V
.
Answer: Option A VIII - Diodes and Applications 44. Voltage lags current in an RLC circuit when it acts: A.
capacitively
B.
resistively
C.
inductively
D.
resonantly
1. What is a varistor?
Answer: Option A
.
A.
a voltage-dependent resistor
B.
a voltage-dependent diode
C.
a current-dependent resistor
D.
a current-dependent diode
Answer: Option A
. 45.
2. Which type of transformer is required to create a 180 degree input t
What is the bandwidth of the circuit in the given circuit? A.
11.6 Hz
B.
275.9 Hz
C.
1.5 kHz
D.
3.2 kHz
A.
center-tapped secondary
B.
step-down secondary
C.
stepped-up secondary
D.
split winding primary
Answer: Option A
.
6.
3. What circuit activity may shift a characteristic curve so that diode operating points are different? A.
higher power (heat)
B.
higher resistance
C.
lower voltage
D.
lower current
Answer: Option A
.
4. What is wrong with this diode?
7. In a power supply diagram, which block indicates a smooth dc output?
A.
open
B.
short
C.
nothing
D.
not enough data
Answer: Option C
A.
transformer
B.
filter
C.
rectifier
D.
regulator
Answer: Option D
.
8. If a 169.7 V half-wave peak has an average voltage of 54 V, what is the average of two full-wave peaks?
.
A.
119.9 V
B.
108.0 V
C.
115.7 V
D.
339.4 V
5. The dc current through each diode in a bridge rectifier equals: A.
the load current
B.
half the dc load current
C.
twice the dc load current
D.
one-fourth the dc load current
Answer: Option A
Answer: Option B
.
9. What is the current through the LED?
thus vary the capacitance is called a A.
varactor diode
B.
tunnel diode
C.
zener diode
D.
switching diode
Answer: Option A
A.
0 mA
B.
23 mA
C.
18 mA
D.
13 mA
.
13. A filtered full-wave rectifier voltage has a smaller ripple than does a half-wave rectifier voltage for the same load resistance and capacitor values because:
Answer: Option D
.
10. The characteristic curve for the complex model of a silicon diode shows that A.
the barrier potential is 0 V
B.
the barrier potential stays fixed at 0.7 V
C.
the barrier potential increases slightly with an increase in current
D.
the barrier potential decreases slightly with an increase in current
higher voltage sources
B.
current limiting resistors
C.
more dopants
D.
higher current sources
there is a shorter time between peaks
B.
there is a longer time between peaks
C.
the larger the ripple, the better the filtering action
D.
none of the above
Answer: Option A
.
14. Testing a good diode with an ohmmeter should indicate
Answer: Option C 11. Since diodes are destroyed by excessive current, circuits must have: A.
A.
A.
high resistance when forward or reverse biased
B.
low resistance when forward or reverse biased
C.
high resistance when reverse biased and low resistance when forward biased
D.
high resistance when forward biased and low resistance when reverse biased
Answer: Option C
Answer: Option B .
.
15. The peak inverse voltage (PIV) across a nonconducting diode in a bridge rectifier equals approximately: 12. A diode for which you can change the reverse bias, and
A.
half the peak secondary voltage
B.
twice the peak secondary voltage
C.
the peak value of the secondary voltage
D.
four times the peak value of the secondary voltage
Answer: Option B
. Answer: Option C 16. What is the current through the diode?
19. A pn junction allows current flow when
A.
1 mA
B.
0.975 mA
C.
0.942 mA
D.
0.0 mA
A.
the p-type material is more positive than the ntype material
B.
the n-type material is more positive than the ptype material
C.
both the n-type and p-type materials have the same potential
D.
there is no potential on the n-type or p-type materials
Answer: Option A
.
Answer: Option A
. 20. What is the current through the zener diode?
17. Electrons in the outermost orbit or shell of an atom are called A.
free electrons
B.
negative ions
C.
valence electrons
D.
conduction band electrons
Answer: Option C
.
A.
0 mA
B.
7 mA
C.
8.3 mA
D.
13 mA
Answer: Option B 21. When a diode is forward biased, the voltage across it
18. Shunting the ac component away from the load is the task of a: A.
transformer
B.
filter
C.
regulator
D.
rectifier
A.
is directly proportional to the current
B.
is inversely proportional to the current
C.
is directly proportional to the source voltage
D.
remains approximately the same
Answer: Option D
25. When checking a diode, low resistance readings both ways indicate the diode is:
.
22. Why is heat produced in a diode? A.
due to current passing through the diode
B.
due to voltage across the diode
C.
due to the power rating of the diode
D.
due to the PN junction of the diode
A.
open
B.
satisfactory
C.
faulty
D.
not the problem
Answer: Option C 26. In a diode schematic, the anode is represented by a(n):
Answer: Option A
A.
triangle
B.
vertical line
C.
zig-zag line
D.
element indicator
. Answer: Option A
23. The arrow in the schematic symbol of a diode points to A.
the n-type material, which is called the anode
B.
the n-type material, which is called the cathode
C.
the p-type material, which is called the anode
D.
the p-type material, which is called the cathode
.
27. An IC regulator receives an overload; it will:
Answer: Option C
A.
shut down
B.
compensate for heat
C.
provide more voltage
D.
sample and adjust
. Answer: Option A
24. The diode schematic arrow points to the: A.
trivalent-doped material
B.
positive axial lead
C.
anode lead
D.
cathode lead
Answer: Option D
.
.
28. With full-wave rectification, current through the load resistor must be: A.
in opposite directions
B.
to the external load
C.
from the reverse biased diode
D.
in the same direction
Answer: Option D
.
B.
60 pps
C.
90 pps
D.
120 pps
Answer: Option B
29. A characteristic curve is the result of a current versus voltage plot of diode activity, which begins at the: A.
3rd quadrant
B.
current plot
C.
graph origin
D.
voltage plot
.
3 What is the peak output voltage for this half-wave 3. rectifier?
Answer: Option C
.
30.
Rectifier output polarity depends upon:
A.
1V
B.
7.8 V
A.
cycles of input
C.
10.9 V
B.
capacitor polarity
D.
15.6 V
C.
half or full wave
D.
diode installation
Answer: Option D 31. With a 12 V supply, a silicon diode, and a 370ohm resistor in series, what voltage will be dropped across the diode? A.
0.3 V
B.
0.7 V
C.
0.9 V
D.
1.4 V
Answer: Option B
.
34. Thermal shutdown occurs in an IC regulator if:
Answer: Option B
.
A.
power dissipation is too high
B.
internal temperature is too high
C.
current through the device is too high
D.
load resistance increases
Answer: Option B
. 32. If the frequency of the applied ac signal to a half-wave rectifier is 60 Hz, the frequency of the pulsating dc output will be A.
30 pps
35. The conduction band is closest to the valence band in A.
semiconductors
B.
conductors
C.
insulators
D.
The distance is the same for all of the above.
39. What is wrong with this circuit?
Answer: Option B 3 What is the percent of regulation if Vnl = 20 V and 6. Vfl = 19.8 V? A.
0%
B.
1%
C.
.1%
D.
5%
Answer: Option B
A.
The zener is open.
B.
The zener is shorted.
C.
nothing
D.
not enough data
. Answer: Option A
37. With a half-wave rectified voltage across the load resistor, load current flows for what part of a cycle? A.
0 degrees
B.
90 degrees
C.
180 degrees
D.
360 degrees
.
40. The voltage where current may start to flow in a reverse-biased pn junction is called the
Answer: Option C
A.
breakdown voltage
B.
barrier potential
C.
forward voltage
D.
biasing voltage
. Answer: Option A 41. Providing a constant output regardless of ac input or load resistance changes is the function of a: 38. Which of the following circuits would require the least amount of filtering? A.
A half-wave rectifier
B.
A full-wave rectifier
C.
A bridge rectifier
D.
A full-wave rectifier and a bridge rectifier
A.
transformer
B.
filter
C.
regulator
D.
rectifier
Answer: Option C
. Answer: Option D
.
42. When a diode is destroyed it has infinite impedance. When damaged by heat it will probably:
A.
short
B.
conduct more
C.
conduct less
D.
open
D.
All of the above
Answer: Option D 46. In a power supply diagram, which block indicates a pulsating dc output?
Answer: Option A
A.
transformer
B.
filter
C.
rectifier
D.
regulator
Answer: Option C .
.
43. The area at the junction of p-type and n-type materials that has lost its majority carriers is called the A.
barrier potential
B.
depletion region
C.
n region
D.
p region
47. List three diode packages:
Answer: Option B
.
A.
clip package, DIP, small current package
B.
DIP, small current package, large current package
C.
small current package, large current package, and SIP
D.
small current package, large current package, clip package
Answer: Option D
. 44. DC power should be connected to forward bias a diode as follows: A.
– anode, + cathode
B.
– cathode, – anode
C.
+ anode, – cathode
D.
+ cathode, + anode
48. The mimicking of an open/closed switch by a diode allows alternating current to be: A.
rectified
B.
regulated
C.
controlled
D.
attenuated
Answer: Option C Answer: Option A
. IX - Operational Amplifiers 1. An ideal operational amplifier has 45. At any given time in an intrinsic piece of semiconductor material at room temperature A.
electrons drift randomly
B.
recombination occurs
C.
holes are created
A.
infinite output impedance
B.
zero input impedance
C.
infinite bandwidth
D.
All of the above
. Answer: Option C
.
2. Another name for a unity gain amplifier is: A.
difference amplifier
B.
comparator
A.
sine wave
C.
single ended
B.
square wave
D.
voltage follower
C.
sawtooth wave
D.
triangle wave
Answer: Option D Answer: Option D . .
3. The open-loop voltage gain (Aol) of an op-amp is the A.
external voltage gain the device is capable of
B.
internal voltage gain the device is capable of
C. D.
5. A series dissipative regulator is an example of a: A.
linear regulator
B.
switching regulator
most controlled parameter
C.
shunt regulator
same as Acl
D.
dc-to-dc converter
Answer: Option B
Answer: Option A 6. What is this circuit?
.
4 What is the output waveform?
A.
a low-pass filter
B.
a high-pass filter
C.
a bandpass filter
D.
a band-stop filter
.
Answer: Option D 10. .
7. A noninverting closed-loop op-amp circuit generally has a gain factor: A.
less than one
B.
greater than one
C.
of zero
D.
equal to one
Decreasing the gain in the given circuit could be achieved by
Answer: Option B
.
A.
reducing the amplitude of the input voltage
B.
increasing the value of the feedback resistor
C.
increasing the value of the input resistor
D.
removing the feedback resistor
Answer: Option C 11. If ground is applied to the (+) terminal of an inverting op-amp, the (–) terminal will:
8. In order for an output to swing above and below a zero reference, the op-amp circuit requires: A.
a resistive feedback network
B.
zero offset
C.
a wide bandwidth
D.
a negative and positive supply
A.
not need an input resistor
B.
be virtual ground
C.
have high reverse current
D.
not invert the signal
Answer: Option B
.
Answer: Option D
. 12. An astable multivibrator is also known as a:
9. Op-amps used as high- and low-pass filter circuits employ which configuration? A.
noninverting
B.
comparator
C.
open-loop
D.
inverting
A.
one-shot multivibrator
B.
free-running multivibrator
C.
bistable multivibrator
D.
monostable multivibrator
Answer: Option B Answer: Option D
. Answer: Option A
13. With negative feedback, the returning signal: A.
aids the input signal
B.
is proportional to output current
C.
opposes the input signal
D.
is proportional to differential voltage gain
.
17. If a noninverting amplifier has an RIN of 1000 ohms and an RFB of 2.5 kilohms, what is the RIN voltage when 1.42 mV is applied to the correct input?
Answer: Option C
.
A.
3.5 mV
B.
ground
C.
1.42 mV
D.
0.56 mV
Answer: Option C 14. What starts a free-running multivibrator? A.
a trigger
B.
an input signal
C.
an external circuit
D.
nothing
.
18. Input impedance [Zin(I)] of an inverting amplifier is approximately equal to: Answer: Option D
.
A.
Ri
B.
Rf + Ri
C.
∞
D.
Rf – Ri
Answer: Option A 15. A portion of the output that provides circuit stabilization is considered to be: A.
negative feedback
B.
distortion
C.
open-loop
D.
positive feedback
.
19. The closed-loop voltage gain of an inverting amplifier equals: Answer: Option A 16. How many leads does the TO-5 metal can package of an operational amplifier have?
A.
the ratio of the input resistance to the feedback resistance
A.
8, 10, or 12
B.
the open-loop voltage gain
B.
6, 8, or 10
C.
the feedback resistance divided by the input resistance
C.
8 or 14
D.
the input resistance
D.
8 or 16
Answer: Option C
.
20 What is the cutoff frequency of this low-pass filter? .
A.
4.8 kHz
B.
3.8 kHz
C.
2.8 kHz
D.
1.8 kHz
Answer: Option D 21 All of the following are basic op-amp input modes of . operation EXCEPT A.
inverting mode
B.
common-mode
C.
double-ended
D.
single-ended
A.
15 V
B.
5V
C.
–5 V
D.
–15 V
Answer: Option C
.
23. A circuit whose output is proportional to the difference between the input signals is considered to be which type of amplifier? A.
common-mode
B.
darlington
C.
differential
D.
operational
Answer: Option C
Answer: Option A .
.
24. With negative feedback, the returning signal
22.What is the output voltage?
A.
is proportional to the output current
B.
is proportional to the differential voltage gain
C.
opposes the input signal
D.
aids the input signal
Answer: Option C
.
25.
C.
sawtooth wave
D.
triangle wave
What is the output waveform? Answer: Option B
.
28. The ratio between differential gain and common-mode gain is called:
A.
sine wave
B.
square wave
C.
+15 V
D.
–15 V
A.
amplitude
B.
differential-mode rejection
C.
common-mode rejection
D.
phase
Answer: Option C Answer: Option A 26. The voltage follower has a: A.
closed-loop voltage gain of unity
B.
small open-loop voltage gain
C.
closed-loop bandwidth of zero
D.
large closed-loop output impedance
.
2 What is the frequency of this 555 astable 9. multivibrator?
Answer: Option A
.
2 What is the output waveform of the 7. circuit?
A.
sine wave
B.
square wave
A.
278 Hz
B.
178 Hz
C.
78 Hz
D.
8 Hz
Answer: Option B
33. If the input to a comparator is a sine wave, the output is a:
.
30. If the gain of a closed-loop inverting amplifier is 3.9, with an input resistor value of 1.6 kilohms, what value of feedback resistor is necessary? A.
6240 ohms
B.
2.4 kilohms
C.
410 ohms
D.
0.62 kilohms
A.
ramp voltage
B.
sine wave
C.
rectangular wave
D.
sawtooth wave
Answer: Option C
. Answer: Option A 31. In an open-loop op-amp circuit, whenever the inverting input (–) is negative relative to the noninverting input (+), the output will: A.
34. What three subcircuits does a phase locked loop (PLL) consist of? A.
phase comparator, comparator, and VCO
B.
phase comparator, bandpass filter, and VCO
C.
phase comparator, bandpass filter, and demodulator
D.
phase comparator, low-pass filter, and VCO
swing negative
B.
close the loop
C.
be balanced
D.
swing positive
Answer: Option D
.
32. With a differential gain of 50,000 and a common-mode gain of 2, what is the commonmode rejection ratio? A.
–87.9 dB
B.
–43.9 dB
C.
43.9 dB
D.
87.9 dB
Answer: Option D
.
Answer: Option D
.
35. The major difference between ground and virtual ground is that virtual ground is only a: A.
voltage reference
B.
current reference
C.
power reference
D.
difference reference
39. When a capacitor is used in place of a resistor in an opamp network, its placement determines:
Answer: Option A 3 If an op-amp has one input grounded and the 6. other input has a signal feed to it, then it is operating as what? A.
Common-mode
B.
Single-ended
C.
Double-ended
D.
Noninverting mode
A.
open- or closed-loop gain
B.
integration or differentiation
C.
saturation or cutoff
D.
addition or subtraction
Answer: Option B
.
Answer: Option B
. 40.
37. If the feedback/input resistor ratio of a feedback amplifier is 4.6 with 1.7 V applied to the noninverting input, what is the output voltage value? A.
7.82 V
B.
saturation
C.
cutoff
D.
9.52 V
Answer: Option D
.
What value of input resistance is needed in the given circuit to produce the given output voltage? A.
50
B.
4k
C.
4.08 k
D.
5k
Answer: Option B
38. The Schmitt trigger is a two-state device that is used for: A.
pulse shaping
B.
peak detection
C.
input noise rejection
D.
filtering
41. The commonmode voltage gain is
A.
smaller than differential voltage gain
B.
equal to voltage gain
C.
greater than differential voltage gain
Answer: Option A
.
D.
None of the above
B.
be less than the capture frequency
C.
come within the capture range
D.
be greater than the capture frequency
Answer: Option A
.
42. How many logic states does an S-R flip-flop have? A.
2
B.
3
C.
4
D.
5
Answer: Option C
.
Answer: Option C 45. An ideal amplifier should have: .
43. An output that is proportional to the addition of two or more inputs is from which type of amplifier? A .
differentiat or
B .
difference
C .
summing
D .
analog subtractor
A.
high input current
B.
zero offset
C.
high output impedance
D.
moderate gain
Answer: Option B 46. A differential amplifier has a common-mode gain of 0.2 and a common-mode rejection ratio of 3250. What would the output voltage be if the single-ended input voltage was 7 mV rms?
Answer: Option C
A.
1.4 mV rms
B.
650 mV rms
C.
4.55 V rms
D.
0.455 V rms
Answer: Option C
.
. 44. In a PLL, to obtain lock, the signal frequency must: A.
come within the lock range
47. The magnitude of closed-loop voltage gain (Acl) of an inverting amplifier equals: A.
the ratio of the input resistance to the feedback
resistance B.
the open-loop voltage gain Aol
C.
the feedback resistance divided by the input resistance
D.
the input resistance
D.
difference between two base currents
Answer: Option D X - QUANTITIES AND UNITS 1. Derived units are obtained from various combinations of
Answer: Option C
.
A.
electrical quantities
B.
fundamental units
C.
metric prefixes
D.
international standards
Answer: Option B 48. What is the difference between common-mode and differential-mode input signals? A.
phase relationship
B.
voltage
C.
current
D.
apparent power
.
2. Which of the following metric prefixes could replace 10 –9? Answer: Option A
.
A.
Nano
B.
Mega
C.
Kilo
D.
Micro
Answer: Option A
. 49. A circuit that uses an amplifier with passive filter elements is called a(n): A.
relaxation oscillator
B.
signal generator
C.
differential amplifier
A.
of expressing a very large number
D.
active filter
B.
of expressing a very small number
C.
used to make calculations with large and small numbers
D.
All of the above
3. Scientific notation is a method
Answer: Option D
Answer: Option D
.
. 50. The input offset current equals the A.
average of two base currents
B.
collector current divided by the current gain
C.
difference between two base-emitter voltages
4. If you drop a 5 when rounding a number, you are using the A.
round-to-even rule
B.
significant digit rule
A.
36.4 × 107
C.
round-off rule
B.
116.5 × 104
D.
retained digit rule
C.
28.39 × 103
D.
1.165 × 105
Answer: Option A Answer: Option D . .
5. 7200 mV is the same as A.
7.2
B.
7.2 V
C.
7,200,000 V
D.
0.0072
V
9. When using the terms "accuracy" and "precision" for measurements
V
A.
"precision" implies less measurement error than "accuracy"
B.
"accuracy" implies less measurement error than "precision"
C.
"precision" measures the repeatability of a measurement
D.
both terms mean the same thing
Answer: Option B 6. A measure of the repeatability of a measurement of some quantityAnswer: is Option C A.
error
B.
precision
C.
accuracy
D.
significant .
Answer: Option B
10. The difference between scientific and engineering notation is
.
7. Another name for "fundamental units" is A.
base units
B.
atoms
C.
the metric system
D.
letter symbols
A.
powers of ten representation
B.
single vs. multiple digits before decimal point
C.
groupings of multiples of three digits
D.
All of the above
Answer: Option D 11. The number 14.8 can also be expressed as
Answer: Option A
.
A.
1.48 × 10–1
B.
1.48 × 100
C.
1.48 × 101
D.
1.48 × 102
Answer: Option C
. 3
4
8. Adding 27.5 × 10 to 8.9 × 10 equals
D.
290 mA
12. The digits in a measured number that are known to be correct are Answer: called Option C 16. A. accuracy digits B.
significant digits
C.
error digits
D.
precision digits
Answer: Option B
.
13. Which of the following is expressed in engineering notation? A.
470 × 105
B.
82 × 10–2
C.
9.1 × 10–6
D.
14.7 × 108
17. Pico is what relation to micro? A.
one-tenth
B.
one-hundredth
C.
one-thousandth
D.
one-millionth
Answer: Option D
Answer: Option C
XI - Ohm's Law 1. "Half-splitting" is
.
14. The unit for frequency is the A.
hertz
B.
ampere
C.
watt
D.
second
Answer: Option A
a means for nuclear fuel cells to produce electricity
B.
a means of isolating a problem in a circuit
C.
a means for reducing a high ac voltage to a low dc voltage
D.
a means of limiting current in a circuit
Answer: Option B
.
.
15.
A.
Add 21 mA and 8000
2. If doubling the voltage across a resistor doubles the A and express the result in milliamperes.current through the resistor then
A.
21.8 mA
A.
the resistor value decreased
B.
218 mA
B.
the resistor value did not change
C.
29 mA
C.
the resistor value increased
D.
What is the power in the given circuit?
it is impossible to determine the change in the resistor value
Answer: Option B
A.
3.6 W
B.
35 W
C.
175 W
D.
245 W
. Answer: Option B 6. What is the kilowatt-hour consumption of a 40 W lamp if it remains on for 1750 h? 3. If the voltage across a fixed value of resistance is increased five times, what does the current do? A.
It increases by a factor of five.
B.
It decreases by a factor of five.
C.
It stays the same.
D.
Not enough information
A.
43.75
B.
70
C.
43,750
D.
70,000
Answer: Option B
(1,750 x 40)/1000 = 70 kilowatt-hour. Answer: Option A
7. A damaged resistor
.
4. If the resistance in a circuit with constant voltage increases, the current will A.
increase
B.
decrease
C.
stay the same
D.
Not enough information
A.
may appear burned
B.
may have an increased resistance value
C.
may be checked with an ohmmeter
D.
All of the above
Answer: Option D
. Answer: Option B
.
5.
8. Power supplies differ from batteries in that A.
power supply output voltages are ac and not dc
B.
power supply voltages are not stable
C.
power supplies are low-current devices
D.
None of the above
Answer: Option D
.
B.
80 W
C.
500 W
D.
16 kW
Answer: Option A
9.
.
12. Ohm's law describes the mathematical relationship between What is the resistor value in the given circuit?
A.
ohms, kilohms, and megohms
B.
resistor size and resistor value
A.
200
C.
resistance, voltage, and current
B.
1k
D.
none of the above
C.
2k
D.
4k
Answer: Option C
Answer: Option C
.
. 13. Energy is defined as the ability to
10. If voltage across a resistance doubles
A.
produce heat
B.
produce light
A.
the current is halved
C.
produce sound
B.
the resistance doubles
D.
All of the above
C.
the current is unchanged
D.
none of the above
Answer: Option D 11 .
Answer: Option D
.
14. What electromotive force would cause 20 A of current to flow through a 500 resistor?
What is the power in the given circuit? A.
32 W
A.
0.04 V
B.
2.5 V
C.
25.0 V
D.
10,000 V
18. Answer: Option D
.
15. The rate at which work is performed is called A.
current
B.
energy
C.
power
D.
voltage
What is the power in the given circuit?
Answer: Option C 16. A battery's capacity to deliver power is measured in A.
kWh
B.
Ah
C.
Wh
D.
Vh
Answer: Option B
A.
3.92 kW
B.
280 W
C.
28.6 W
D.
9.8 W
Answer: Option D
.
. 19. If current through a resistance is halved
17. Power supplies are regulated to prevent the output voltage from changing due to changes in the A.
line voltage
B.
supply load
C.
frequency
D.
both line voltage and supply load
A.
the resistance is halved
B.
the voltage is halved
C.
the voltage doubles
D.
none of the above
Answer: Option B
. Answer: Option D
.
20. Ohm's law is a relationship between A.
voltage, current, and time
B.
power, current, and resistance
C.
resistance, time, and current
D.
voltage, current, and resistance
Answer: Option D
If the voltage in the given circuit was cut in half, what would the current equal? A.
10 mA
B.
30 mA
C.
60 mA
D.
90 mA
A.
12,000
B.
83,330 T
C.
0T
D.
More information is needed in order to find flux density.
T
Answer: Option A
.
4. How much flux is there in a magnetic field when its flux
Answer: Option B
density is 5000 mm2?
XI - MAGNETISM AND ELECTROMAGNETISM 1. Permeability is the inverse equivalent of which electrical term? A.
Voltage
B.
Current
C.
Resistance
D.
Conductance
T and its cross-sectional area is 300
A.
16.67 mWb
B.
5.0
C.
3.0 mWb
D.
1.5
Wb
Wb
Answer: Option D
Answer: Option C
.
.
2. Which electromagnetic device uses brushes and a commutator? A.
A speaker
B.
A dc generator
C.
A relay
D.
A solenoid
5.
What are the effects of moving a closed wire loop through a magnetic field? A.
A voltage is induced in the wire.
B.
A current is induced in the wire.
C.
The polarity across the wire depends on the direction of motion.
D.
All of the above
Answer: Option B 6. The Hall effect .
3. What is the flux density of a magnetic field whose flux is 3000 µWb and cross-sectional area is 0.25 m2?
Answer: Option D
A.
is a phenomenon with no practical applications
B.
is used in various sensor applications
C.
can develop potentials of thousands of volts
D.
is the basis for solar cell
operation
D.
152 At
Answer: Option B
Answer: Option B
.
.
7. "Series" and "parallel" as applied to dc motors refer to A. B.
10. A Hall effect sensor
the connection of the motor and controller the connection of the field coil and armature windings
C.
the connection of the brush and commutator
D.
the connection of the motor batteries
Answer: Option B
A.
exists only in theory
B.
is a noncontacting magnetic sensor
C.
can operate only a few times before failure
D.
produces very large voltages
Answer: Option B 11. Which two values are plotted on a BH curve graph?
.
8. The component that produces power in an electromagnetic generator is called the A.
armature
B.
field winding
C.
commutator
D.
brush
Answer: Option A
A.
13.33 mAt
B.
300 At
C.
75 At
Reluctance and flux density
B.
Permeability and reluctance
C.
Magnetizing force and permeability
D.
Flux density and magnetizing force
Answer: Option D
.
12. Which electromagnetic device has a flexible cone?
.
9. What is the magnetomotive force in a 150-turn coil of wire with 2 A flowing through it?
A.
A.
A speaker
B.
A dc generator
C.
A relay
D.
A solenoid
Answer: Option A
.
13. What is the reluctance of a material that has a length of 0.045 m, a cross-sectional area of 0.015 m2, and a permeability of 2500 µWb/At·m? A.
833.33 µAt/Wb
B.
0.27 At/Wb
A.
A speaker
C.
1200 At/Wb
B.
A dc generator
D.
More information is needed in order to find the reluctance.
C.
A relay
D.
A solenoid
12. Which electromagnetic device has a flexible cone?
Answer: Option C Answer: Option A
. .
14. The unit of flux density is known as A.
magnetomotive force
B.
a weber
C.
a maxwell
D.
a tesla
13. What is the reluctance of a material that has a length of 0.045 m, a cross-sectional area of 0.015 m2, and a permeability of 2500 µWb/At·m?
Answer: Option D
A.
833.33 µAt/Wb
B.
0.27 At/Wb
C.
1200 At/Wb
D.
More information is needed in order to find the reluctance.
Answer: Option C
.
. 15. What do you call the characteristic of a magnetic material whereby a change in magnetization lags the application of a magnetizing force? A.
Hysteresis
B.
Induction
C.
Retentivity
D.
Reluctance
14. The unit of flux density is known as
Answer: Option A 11. Which two values are plotted on a B-H curve graph? A.
Reluctance and flux density
B.
Permeability and reluctance
C.
Magnetizing force and permeability
D.
Flux density and magnetizing force
A.
magnetomotive force
B.
a weber
C.
a maxwell
D.
a tesla
Answer: Option D
. Answer: Option D
.
15. What do you call the characteristic of a magnetic material whereby a change in magnetization lags the
application of a magnetizing force? A.
Hysteresis
B.
Induction
C.
Retentivity
D.
Reluctance
1.
What type of waveform is shown in the given circuit?
Answer: Option A 16. Which electromagnetic device has a movable iron core called a plunger? A.
A speaker
B.
A dc generator
C.
A relay
D.
A solenoid
A.
Sine wave
B.
Square wave
C.
Triangle wave
D.
Sawtooth wave
Answer: Option C Answer: Option D . .
2. In both induction and synchronous ac motors 17. Which electromagnetic device contains an armature? A.
A speaker
B.
A dc generator
C.
A relay
D.
A solenoid
A.
the operating speed is very steady
B.
the stator magnetic field is stationary
C.
the stator magnetic field rotates
D.
the "squirrel cage" forms the rotor
Answer: Option C Answer: Option B . .
3. 18. The polarity of induced voltage while a field is collapsing is A.
independent of the force creating the field
B.
opposite to the force creating the field
C.
identical to the force creating the field
D.
present only if the force is stationary
Answer: Option B XIII - Alternating Current and Voltage
What is the peak-to-peak voltage of the waveform in the given circuit? A.
2V
B.
4V
C.
6V
D.
8V
Answer: Option D
the given circuit. .
A.
5 V/ms
B.
2.5 V/ms
C.
2.5 V/s
D.
5 V/s
4. Most practical alternators generate electricity from A.
a coil rotating within a magnetic field
B.
a magnetic field rotating around fixed windings
C.
a permanent magnet rotating within a varying electromagnetic field
D.
none of the above
Answer: Option B
.
Answer: Option B 8. A rectangular wave that has a duty cycle of 50% could be called a .
A.
"c" wave
B.
sawtooth wave
C.
square wave
D.
triangular wave
5. A half-cycle average voltage of 12 V is equal to what rms voltage? A.
13.33 V
B.
8.48 V
C.
18.84 V
D.
7.64 V
Answer: Option A 6. What is the instantaneous peak voltage at 250° on a 6 V peak sine wave? A.
+5.64 V
B.
–5.64 V
C.
+26.13 V
D.
–26.13 V
Answer: Option C
.
9.
Calculate the duty cycle of the repetitive pulse waveform in the given circuit.
Answer: Option B
.
A.
8.33%
B.
0%
C.
33.33%
D.
25%
Answer: Option D
. 7.
10.
The effective value of a sine wave is equal to A.
Calculate the positive-going slope of the waveform in
0.707 of peak voltage
B.
0.636 of peak voltage
C.
sin 45° of peak voltage
D.
both 0.707 of peak voltage and sin 45° of peak voltage
13.
Answer: Option D
11.
What is the peak voltage across R3 in the given circuit?
What is the dc voltage of the waveform in the given circuit? A.
2V
B.
4V
C.
6V
D.
8V
A.
1.2 V
B.
5V
C.
7V
D.
12 V
Answer: Option B
.
Answer: Option C
14 .
.
12. What is the fourth harmonic of a fundamental frequency of 400 Hz? A.
100 Hz
B.
4 kHz
C.
4 Hz
D.
1.6 kHz
Answer: Option D
.
Which point is the trailing edge of the repetitive pulse waveform in the given circuit? A.
Point A
B.
Point B
C.
Point C
D.
Point D
Answer: Option A
.
15. A single-phase induction motor A.
is self-starting
B.
operates at a fixed speed
C.
is less reliable than a three-phase synchronous motor
D.
none of the above
3. Answer: Option D
1What is the average voltage when a rectangular 6wave's base line voltage is 20 V, its peak-to-peak .voltage is 50 V, and its duty cycle is 20%? A.
26 V
B.
30 V
C.
40 V
D.
45 V
What is the voltage drop across R1 in the given circuit?
Answer: Option B XIV - RC Circuits 1. In a 20 Vac series RC circuit, if 20 V is read across the resistor and 40 V is measured across the capacitor, the applied voltage is A.
45 Vac
B.
50 Vac
C.
60 Vac
D.
65 Vac
A.
10 V
B.
4.80 V
C.
4.00 V
D.
5.80 V
Answer: Option D
.
4. Power that is measured in volt-amperes is called Answer: Option A
.
A.
impedance power
B.
reactive power
C.
true power
D.
apparent power
Answer: Option D 2. Which of the following is the reference vector for parallel RC circuits? A.
R
B.
V
C.
I
D.
XC
.
Answer: Option B 5. As frequency increases
.
A.
both series and parallel RC impedance decrease
B.
series RC impedance decreases and parallel RC impedance increases
C.
series RC impedance increases and parallel RC impedance decreases
D.
both series and parallel RC impedance increase
Answer: Option A
6. Answer: Option C
.
Calculate the magnitude of the impedance in the given circuit. A.
24.1 M
B.
10 M
C.
26.1 M
D.
0
9.
Answer: Option C
Which circuit is represented by the frequency response curve in the given figure?
.
A.
High-pass filter
B.
Low-pass filter
C.
Band-pass filter
7. D.
Band-stop filter
Answer: Option B
. Calculate the phase angle in the given circuit. A.
0°
B.
90°
C.
22.52°
D.
67.48°
10 .
Answer: Option D
.
8. What is the phase angle for a parallel circuit consisting of a 500 kHz, 5 Vac source with a 47 pF capacitor, and a 4.7 k resistor in parallel? A.
55.3°
B.
–55.3°
C.
34.8°
D.
–34.8°
What is the phase angle in the given circuit? A.
14.95°
B.
36.88°
C.
0°
D.
90°
Answer: Option A
11 .
C.
The current lags the source voltage.
D.
The resistor voltage lags the current.
Answer: Option B
. What is the current through XC1 in the given circuit? A.
32.2 mA
B.
16 mA
C.
12 mA
D.
48 mA
14.
Answer: Option A
If the frequency increases in the given circuit, how would the total current change?
.
A.
The total current would increase.
B.
The total current would decrease.
C.
The total current would remain the same.
D.
More information is needed in order to predict how the total current would change.
12.
Answer: Option A
What is the total current in the given circuit? A.
0.28 A
B.
0.399 A
C.
909 A
D.
0.2 A
Answer: Option A
.
15. What is the effect of increasing the resistance in a series RC circuit? A.
There will be no effect at all.
B.
The current will increase.
C.
The phase shift will decrease.
D.
The input voltage will increase.
. Answer: Option C
13. Which statement about a series RC circuit is true? A.
The capacitor's voltage drop is in phase with the resistor's voltage drop.
B.
The current leads the source voltage.
RL Circuits
1. As frequency increases A.
both series and parallel RL impedance decrease
B.
series RL impedance decreases and parallel RL impedance increases
C.
series RL impedance increases and parallel RL impedance decreases
D.
both series and parallel RL impedance increase
.
4. If XL= 100
Answer: Option D
.
A.
141.4
B.
14.14
C.
100
D.
200
and R = 100
, then impedance will be
Answer: Option A
2. .
5.
Calculate the voltage dropped across R1 in the given circuit. A.
14 V
B.
26.8 V
C.
28 V
D.
0V
Which of the following statements is true if the inductor shorts out in the circuit in the given circuit?
Answer: Option B
.
6.
A.
Each component drops 5 V.
B.
The impedance equals 0
C.
The power factor equals 1.
D.
The phase angle equals 90°.
.
Answer: Option C
3. What is the true power of a 24 Vac parallel RL circuit when R = 45 and XL = 1100 ? A.
313.45 W
B.
12.8 W
C.
44.96 W
D.
22.3 W
Answer: Option B
Calculate the voltage dropped across L2 in the given circuit. A.
18 V
B.
6V
C.
13.5 V
D.
0V
A.
0.1°
B.
9.0°
C.
61.0°
D.
81.0°
Answer: Option B Answer: Option D . .
7. What is the magnitude of the phase angle of a 24 Vac parallel RL circuit when R = 45 and XL = 1100 ? A.
0.001°
B.
2.3°
C.
87.6°
D.
89.9°
10.
Answer: Option B
. Which of the following statements is true if R1 opens in the circuit in the given circuit?
8.
A.
IL2 increases.
B.
ZT decreases.
C.
VS increases.
D.
VL1 equals 0 V.
Answer: Option D 11.
Which of the following statements is true if the frequency decreases in the circuit in the given circuit? A.
The phase angle decreases.
B.
VR decreases.
C.
IT decreases.
D.
VS decreases.
Which of the following statements is true if R = 100 and XL = 100 in the circuit in the given circuit?
Answer: Option A
.
A.
Each component drops 5 V.
B.
The impedance equals 200
C.
The power factor equals 1.
D.
The phase angle equals 45°.
Answer: Option D 9. What is the magnitude of the phase angle between the source voltage and current when a 100 mH inductor with an inductive reactance of 6 k and a 1 k resistor are in series with a source?
.
.
second coil has an inductance of 105 mH. What is the mutual inductance between the coils?
1 Which of the following statements is true about a lag 2 network? . An increase in frequency causes an increase in A. phase lag. B.
An increase in frequency causes an increase in the magnitude of the output voltage.
C.
A decrease in frequency causes an increase in phase lag.
D.
A decrease in frequency causes a decrease in the magnitude of the output voltage.
A.
3.54 mH
B.
7.88 mH
C.
39.9 mH
D.
189.3 mH
Answer: Option C
.
Answer: Option A XVI - TRANSFORMERS
4. Increasing the number of turns of wire on the secondary of a transformer will
1. When does maximum power transfer happen from the source to the load? A.
When the source resistance is greater than the load resistance
B.
When the source resistance is less than the load resistance
C.
When there is negligible source resistance
D.
When the source resistance equals the load resistance
A.
increase the secondary current
B.
decrease the secondary current
C.
have no effect on the secondary current
D.
increase the primary current
Answer: Option B
.
Answer: Option D
. 5. What is the turns ratio of the transformer needed to match a 1 k source resistance to a 160 load?
2. A transformer is plugged into a 120 V rms source and has a primary current of 300 mA rms. The secondary is providing 18 V across a 10 load. What is the efficiency of the transformer? A.
88%
B.
90%
C.
92%
D.
95%
6.
A.
2.5:1
B.
0.4:1
C.
6.25:1
D.
16:1
Answer: Option B
Answer: Option B
What is the secondary voltage in the given circuit? .
3. The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the
A.
13.3 V rms in phase with the primary
B.
120 V rms in phase with the primary
C.
13.3 V rms out of phase with the primary
D.
120 V rms out of phase with the primary
Answer: Option C
C.
250 mA
D.
1.25 A
Answer: Option C
.
. 7. The transformer turns ratio determines A.
the ratio of primary and secondary voltages
B.
the ratio of primary and secondary currents
C.
the reflected impedance
D.
all of the above
10.
Answer: Option D What is the power dissipated in the primary of the transformer in the given circuit? .
8. Mutual induction is dependent on A.
winding ratios
B.
output polarities
C.
dc voltage levels
D.
current changes
A.
25 mW
B.
500 mW
C.
12.5 W
D.
62.5 W
Answer: Option D 11. A special transformer used to convert unbalanced signals to balanced signals is the
Answer: Option D
.
A.
balun
B.
autotransformer
C.
center-tapped transformer
D.
step-across transformer
Answer: Option A
. 9.
12.
What is the current through the load in the given circuit? A.
500
B.
10 mA
A If the load doubled in value in the given circuit, what reflected resistance would the source see?
A.
80
B.
400
C.
2k
D.
10 k
1.
Answer: Option A
. What voltage will the capacitor charge up to in the given circuit for the single input pulse shown?
13. If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is A.
100 W
B.
50 W
C.
75 W
D.
200 W
Answer: Option A
A.
3.15 V
B.
4.3 V
C.
4.75 V
D.
4.9 V
Answer: Option B
.
. 2. If a periodic pulse waveform is applied to an RC differentiating circuit, which two conditions are possible? 14. A transformer has A.
primary and secondary windings, both of which are considered inputs
B.
primary and secondary windings, both of which are considered outputs
C.
a primary winding used as an output and a secondary winding used as an input
D.
a primary winding used as an input and a secondary winding used as an output
A.
tw
B.
tw = 5
C.
tw
5
or tw < 5
D.
tw
5
or tw < 5
5
or tw > 5 or tw > 5
Answer: Option D
. Answer: Option D
XVII - Time Response of Reactive Circuits 3. An RL integrator and an RC differentiator can act as what types of filters, respectively? A.
low-pass, low-pass
B.
low-pass, high-pass
C.
high-pass, high-pass
D.
high-pass, low-pass
Answer: Option B
C.
3.76 ms
D.
4.7 ms
Answer: Option D
.
. 4. In a repetitive-pulse RC integrator circuit, what would the steady-state voltage equal at the end of the fifth pulse? Assume a Vin of 20 V. A.
1.46 V
B.
14.62 V
C.
20 V
D.
0V
7.
Answer: Option B
.
The given circuit is an
5. What is a circuit that produces short-duration spikes?
6.
A.
A trigger pulse generator
B.
An RL integrator
C.
A timing circuit
D.
A pulse waveform-to-dc converter
A.
RL integrator
B.
RC differentiator
C.
RL differentiator
D.
RC integrator
Answer: Option D
Answer: Option A .
8. Which of the following is true for a capacitor?
In the given circuit, what must the pulse width and time between pulses be to allow the capacitor to completely charge by the end of each pulse and to completely discharge between each pulse? A.
940
B.
2.82 ms
s
A.
A capacitor acts like a short to instantaneous changes in current.
B.
A capacitor's voltage cannot change instantaneously.
C.
A capacitor acts like an open to dc.
D.
All of the above
Answer: Option D
.
How long will it take the capacitor in the given circuit to discharge? A.
16.4
s
B.
32.8
s
C.
65.6
s
D.
82
9. If the capacitor in an RC integrator shorts, the output A.
is at ground
B.
would measure the same as the input
C.
would measure zero volts
D.
None of the above
s
Answer: Option D
Answer: Option A .
. 12 . 10 .
What is the voltage across the inductor in the given circuit on the falling edge of the first input pulse?
What has the voltage across the resistor decayed to by the end of the pulse in the given circuit?
A.
–0.2 V
B.
0.2 V
A.
0V
C.
–9.8 V
B.
0.75 V
D.
9.8 V
C.
5.55 V
D.
14.25 V
Answer: Option A
XVIII - TRANSISTORS AND APPLICATIONS Answer: Option B 11 .
1. The primary function of the bias circuit is to A.
hold the circuit stable at VCC
B.
hold the circuit stable at vin
C.
ensure proper gain is achieved
D.
hold the circuit stable at the designed Q-point
Answer: Option D
.
5. The formula used to calculate the approximate ac resistance of the base-emitter diode (re) is 2. A JFET A.
is a current-controlled device
B.
has a low input resistance
C.
is a voltage-controlled device
D.
is always forward-biased
A.
B.
re
25 mV × IC
C.
Answer: Option C
D.
. Answer: Option A 6. The signal voltage gain of an amplifier, Av, is defined as: A.
3. A source follower has a voltage gain (Av) of A.
AV = gmRd
B.
AV = gmRS
B.
Av = IC × RC
C. C.
D. D.
Answer: Option C Answer: Option C
. .
4. The capacitor that produces an ac ground is called a(n) A.
coupling capacitor
B.
dc open
C.
bypass capacitor
D.
ac open
7. In a class B push-pull amplifier, the transistors are biased slightly above cutoff to avoid A.
crossover distortion
B.
unusually high efficiency
C.
negative feedback
D.
a low input impedance
Answer: Option A Answer: Option C
. .
D. 8. The depletion-mode MOSFET A.
can operate with only positive gate voltages
B.
can operate with only negative gate voltages
C.
cannot operate in the ohmic region
D.
can operate with positive as well as negative gate voltages
provide a high-frequency path to improve the frequency response
Answer: Option B
.
Answer: Option D 12. In order for feedback oscillators to have any practical value, the gain has to be .
9. Three different points are shown on a dc load line. The upper point represents the A.
minimum current gain
B.
quiescent point
C.
saturation point
D.
cutoff point
A.
3
C.
0
D.
Acl
.
13. A two-pole high-pass active filter would have a rolloff rate of
1
Answer: Option B
A.
40 dB/decade
B.
–40 dB/decade
C.
20 dB/decade
D.
–20 dB/decade
. Answer: Option B
10. In an averaging amplifier, the input resistances are
11.
A.
equal to the feedback resistance
B.
less than the feedback resistance
C.
greater than the feedback resistance
D.
unequal
1 .
Answer: Option C A triangular-wave oscillator can consist of an op-amp comparator, followed by a(n) A.
differentiator
B.
amplifier
C.
integrator
D.
multivibrator
Answer: Option C
.
XX - SPECIAL-PURPOSE OP-AMP CIRCUITS
Which circuit is known as a current-to-voltage converter? A.
a
B.
b
C.
c
D.
d
A.
a
B.
b
C.
c
D.
d
Answer: Option D Answer: Option A . .
4. 2. When using an OTA in a Schmitt-trigger configuration, the trigger points are controlled by A.
the Iout
B.
the IBIAS
C.
the Vout
D.
both Iout and IBIAS
This circuit is a setup for
Answer: Option D
A.
an antilog amplifier
B.
a constant-current source
C.
an instrumentation amplifier
D.
an isolation amplifier
. Answer: Option C
3 .
.
Refer the given circuits. Which circuit is known as an OTA?
5.
Refer to Figure 20-2. This circuit is a setup for A.
an antilog amplifier
B.
a constant-current source
C.
an instrumentation amplifier
D.
an isolation amplifier
Answer: Option B
.
8. An instrumentation amplifier has a high
Which circuit is known as a voltage-to-current converter? A.
a
B.
b
C.
c
D.
d
convert dc to highfrequency ac
B.
convert dc to lowfrequency ac
C.
rectify high-frequency ac to dc
D.
produce dual-polarity dc voltages for the input to the demodulator
output impedance
B.
power gain
C.
CMRR
D.
supply voltage
Answer: Option C
Answer: Option B 6. The primary function of the oscillator in an isolation amplifier is to A.
A.
.
9 .
Answer: Option A
. This circuit is a setup for A.
an antilog amplifier
B.
a constant-current source
C.
an instrumentation amplifier
D.
an isolation amplifier
7.
XXI - Measurement, Conversion and Control Answer: Option D
1. What device is similar to an RTD but has a negative temperature co
.
10. Circuits that shift the dc level of a signal are called A.
limiters
B.
clampers
C.
peak detectors
D.
dc converters
Answer: Option B 1 The voltage gain of an OTA can be calculated using the 1 formula .
A.
Strain gauge
B.
Thermistor
C.
Negative-type RTD
D.
Thermocouple
Answer: Option B
.
2. The resistive change of a strain gauge
A.
B.
A.
is based on the weight placed upon it, but can be many thous
B.
is usually no more than 100
C.
is based on the gauge factor, but is typically less than an ohm
D.
has a positive temperature coefficient
Answer: Option C
C.
.
D.
Answer: Option B 3. The silicon-controlled rectifier can be turned off
.
12. In the classic three-op-amp instrumentation amplifier, the differential voltage gain is usually produced by the A.
first stage
B.
second stage
C.
mismatched resistors
D.
output op-amp
Answer: Option A
A.
by a negative gate pulse
B.
by forced commutation
C.
with the off switch
D.
when the breakover voltage is exceeded
Answer: Option B
.
4. The output voltage of a typical thermocouple is A.
less than 100 mV
B.
greater than 1 V
C.
Thermocouples vary resistance, not voltage.
B.
RTDs
D.
None of the above
C.
thermistors
D.
All of the above
Answer: Option A Answer: Option D . .
5. The connections to a thermocouple A.
can produce an unwanted thermocouple effect, which must be compensated for 8. The purpose of compensation for a thermocouple is
B.
produce an extra desirable thermocouple effect
A.
to decrease temperature sensitivity
C.
must be protected, since high voltages are present
B.
to increase voltage output
D.
produce an extra desirable thermocouple effect and must be protected, to cancel sinceunwanted high voltages voltage output of a C. are present thermocouple D.
used for high-temperature circuits
Answer: Option A 6. Answer: Option C
What is the zerovoltage switch used for?
To reduce radiation of high . frequencies A. during turn-on of a high current to a load 9. The change in value of an analog signal during the control conversion process produces To what is called the B. low-voltage A. quantization error circuits B.
resolution error
C.
Nyquist error
D.
sampling error
Answer: Option A
C.
To provide power to a circuit when power is lost
D.
For extremely low-voltage applications
. Answer: Option A
. 10. Which of the following performance specifications applies to a sample-and-hold circuit?
7. Temperature sensing can be achieved by the use of A.
thermocouples
A.
Aperture time
B.
Aperture droop
C.
Feedback
D.
Acquisition jitter
Answer: Option B Answer: Option A 11. RTDs are typically connected with other fixed resistors A.
in a pi configuration
B.
in a bridge configuration
C.
and variable resistors
D.
and capacitors in a filter-type circuit
.
2. How do fixed resistors usually fail?
Answer: Option B
.
A.
slowly over time
B.
by increasing their value
C.
by becoming an open circuit
D.
by increasing their value and becoming an open circuit
Answer: Option C 12. Holding current for an SCR is best described as A.
the minimum current required for turn-off
B.
the current required before an SCR will turn on
C.
the amount of current required to maintain conduction
D.
the gate current required to maintain conduction
.
3. With Ohm's law, if voltage increases and resistance stays the same:
Answer: Option C
.
A.
current remains the same
B.
power decreases
C.
current increases
D.
resistance decreases
Answer: Option C
13. What is the moving part of a linear variable differential transformer? A.
Primary
B.
Secondary
C.
Diaphragm
D.
Core
Answer: Option D
XXII - Resistance and Power
1. The resistivity of copper is: A.
9.9
B.
10.7
C.
16.7
D.
17.0
.
4. Which formula shows a direct proportionality between power and voltage? A.
V = IR
B.
P = VI
C.
P = IR
D.
I = V/R
Answer: Option B
.
Answer: Option C
. 5. With 1 mA of current, what wattage rating should a 470 ohm resistor have? A.
1/4 watt
B.
1/2 watt
C.
1 watt
A.
low and high ohmic value
D.
2 watts
B.
commercial and industrial
C.
low and high power value
D.
fixed and variable
9. What are the two major categories for resistors?
Answer: Option A 6. How is a 3.9 k resistor color-coded? A.
red, white, red, gold
B.
red, green, orange, silver
C.
orange, white, red, gold
D.
orange, green, orange, silver
Answer: Option D
.
Answer: Option C
10.How many connections does a potentiometer have? .
7. What resistor type is found in SIPs and DIPs? A.
metal film
B.
wirewound
C.
metal oxide
D.
thick film
A.
1
B.
2
C.
3
D.
4
Answer: Option C
A potentiometer uses three connections, as opposed to a rheostat, which only employs two. Having three connections allows the potentiometer to vary voltage. Both the potentiometer and the rheostat are classified as variable resistors. 11.What current is flowing in the circuit?
Answer: Option D
.
8. Ohm's law is not: A.
V = IR
B.
I = V/R
C.
R = IV
D.
R = V/I
A.
288 kA
B.
2 kA
C.
50 mA
D.
500
A
Answer: Option D . .
15. Power is defined as: 12. The six basic forms of energy are: A.
light, sun, magnetic, chemical, electrical, and mechanical
B.
electrical, mechanical, light, heat, magnetic, and chemical
C.
electrical, mechanical, sun, heat, chemical, and light
D.
potential, sun, light, chemical, electrical, and mechanical
A.
the rate at which energy is used
B.
watts
C.
energy
D.
the rate at which energy is generated
Answer: Option A 16. What is the most commonly used conductor in electronics? A.
aluminum
B.
copper
C.
gold
D.
silver
Answer: Option B Answer: Option B . .
13. How much energy is stored if 6.24 x 1018 electrons are stored in 4 volts? A.
4 joules
B.
1.56 x 1018 electrons
C.
1.56 coulombs
D.
2.496 x 1019 electrons
17. With Ohm's law, no change in resistance means that current and voltage will be: A.
directly proportional
B.
unable to produce energy
C.
the same
D.
inversely proportional
Answer: Option A Answer: Option A . .
14. With Ohm's law: A.
current is inversely proportional to resistance
B.
resistance is directly proportional to voltage
C.
voltage is indirectly proportional to power
D.
current is directly proportional to resistance
18. A potentiometer has how many leads? A.
1
B.
2
C.
3
D.
4
Answer: Option C Answer: Option A
.
Answer: Option D
. 19. What is the ratio of 13 to 47 expressed in percent? A.
2.76%
B.
27.7%
C.
3.60%
D.
36.1% 23. A conductor's cross-sectional area in circular mils
Answer: Option B
for
.
20. What happens to current and resistance if the voltage doubles? A.
Current doubles and resistance doubles.
B.
Current doubles and resistance is halved.
C.
Current remains the same and resistance doubles.
D.
Current doubles and resistance remains the same.
inch is:
A.
500 cmils
B.
100,000 cmils
C.
1,000,000 cmils
D.
500,000,000 cmils
Answer: Option C
.
24. If a variable resistor's resistance varies in a nonuniform manner as the shaft is moved, it is considered to be: Answer: Option D 21. One problem with mechanically variable resistors is noticeable in audio circuits as:
A.
linear
B.
defective
A.
scratchy noise
C.
not wirewound
B.
lack of bass response
D.
tapered
C.
variable volume
D.
too much treble response
Answer: Option A
Answer: Option D
.
. 25. Power is measured in units of:
22. A color code of orange, orange, orange is for what ohmic value? A.
22 kilohms
B.
3300 ohms
C.
44000 ohms
D.
33 kilohms
A.
joules x charge
B.
joules/work
C.
joules x voltage
D.
joules/time
Answer: Option D 26. How many basic types of resistors exist? A.
1
B.
2
C.
3
D.
4 .
Answer: Option B
30. Components designed to oppose the flow of current are called:
.
27. With a complex circuit, a supply source senses: A.
open circuit components
B.
when voltages need to be increased
C.
only a single resistive connection
D.
when complex currents are needed
A.
insulators
B.
conductors
C.
resistors
D.
heat exchangers
Answer: Option C 31. How many amps are used by a 100 watt, 120 volt light bulb?
Answer: Option C
A.
1.2 amps
B.
12000 amps
C.
830 mA
D.
12 amps
. Answer: Option C
28. How many ohms of resistance allows a current of 720 A to flow when 3.6 kV is applied? A.
200 n
B.
5k
C.
200 k
D.
5M
.
32. The source is 24 volts and the load resistance is 100 . What is the load current?
Answer: Option D
A.
2.4 A
B.
240 mA
C.
24 mA
D.
2.4 mA
. Answer: Option B
29. Which is the most important step utilized when measuring resistors? A.
use the highest possible scale
B.
keep test leads short
C.
zero the meter before using
D.
remove power from the circuit
Answer: Option D
.
33. Resistors are identified as to wattage by: A.
size
B.
color code
C.
types of materials
D.
internal construction Answer: Option A
Answer: Option A . .
38. The load resistance increases. How will the load current change? 34. What type of resistors have a tolerance rating of 5% or greater?
A.
vary
A.
precision
B.
SIP
B.
remain constant
C.
general-purpose
D.
wirewound
C.
increase
D.
decrease
Answer: Option C Answer: Option D . .
35. Resistor tolerance is either printed on the component, or is provided by: 39. What is the power dissipated by a 1.2 k 12 volts across it?
A.
keyed containers
B.
size
A.
12 A
C.
color code
B.
1.2 A
D.
ohmmeter reading
C.
.12 A
D.
12 mA
resistor with
Answer: Option C 36. How many connections does a rheostat have? A.
1
B.
2
C.
3
D.
4
Answer: Option C
. Answer: Option B
.
40. How many joules of energy will a 10 W lamp dissipate in one minute?
37. What are the parts of a rheostat? A.
wiper and resistor track
B.
solenoid and armature
C.
contact and wire wound
D.
center tape and wiper
A.
10 joules
B.
60 joules
C.
600 joules
D.
3600 joules
Answer: Option C 41. Which type of test equipment is used to measure resistors?
A.
ohmmeter
C.
remain the same
B.
ammeter
D.
double
C.
voltmeter
D.
watt meter
Answer: Option A
Answer: Option B
.
. 45. A wire with a smaller cross-sectional area will produce:
42. Resistance is: A.
the opposition to current flow accompanied by the dissipation of heat
B.
symbolized by R, measured in ohms, and directly proportional to conductance
C.
directly proportional to current and voltage
D.
represented by the flow of fluid in the fluid circuit
A.
less heat
B.
more conductance
C.
less resistance
D.
more heat
Answer: Option D 46. A 22-gauge wire will have a diameter in mils of: A.
10.03
B.
22.35
C.
45.26
D.
71.96
Answer: Option A Answer: Option B
. .
43. Electrical equipment is protected against excessive current by a(n): A.
fusible wire link
B.
insulated glass container
C.
metal ended coil
D.
circuit opener
Answer: Option A
.
47. The word work means that: A.
energy has been transferred
B.
it is inversely related to energy
C.
no energy has been transferred
D.
work and energy are not related
Answer: Option A
.
44. If resistance decreases, then current will: A.
decrease
B.
increase
48. A good fuse will have: A.
zero ohms resistance
B.
a medium resistance
C.
a high resistance
D.
an infinite resistance
52. What value of a 1.3 k resistor as measured by a digital voltmeter would be considered within tolerance?
Answer: Option A
A.
1234
B.
1235
C.
1366
D.
1367
. Answer: Option B
49. What property does an incandescent lamp possess? A.
cold resistance
B.
hot resistance
C.
ballast resistance
D.
both cold and hot resistance
.
53. If a calculator display was "0.00263," what would this answer be in percent?
Answer: Option D
A.
0.026%
B.
0.26%
C.
2.63%
D.
26.3%
Answer: Option B
.
. 50. One advantage of a carbon film resistor over a carbon composition resistor is: A.
less circuit noise
B.
smaller size
C.
higher wattage
D.
poor tolerance
54. A 33 k resistor with a 20% tolerance checks out as ok with which of the following ohmmeter readings?
Answer: Option A 51. If a metallic conductor has a positive temperature coefficient of resistance, then: A.
as temperature increases, resistance decreases
B.
as current increases, resistance decreases
C.
as voltage increases, current increases
D.
as temperature increases, resistance increases
A.
26400 ohms
B.
24183 ohms
C.
6600 ohms
D.
39970 ohms
Answer: Option A
.
Answer: Option D 55. For P = V2/R, a decrease in resistance should produce: .
A.
a decrease in power
B.
an increase in ohms
C.
an increase in power
D.
a decrease in current
Answer: Option C 56. After a lamp is turned on, its filament resistance will change to become: A.
less resistive
B.
cooler
C.
brighter
D.
more resistive
A.
opposition to current
B.
opposition to voltage
C.
the same as current
D.
the same as voltage
Answer: Option A
. Answer: Option D
60. The unit designator for resistance value is the:
.
57. Wirewound resistors are usually used in circuits that have: A.
high current
B.
negative temperature coefficients
C.
low power
D.
high voltage
A.
ampere
B.
ohm
C.
volt
D.
watt
Answer: Option B 61. One ampere of current flowing through one ohm of resistance is equal to: A.
1 horsepower
B.
1 Btu
C.
1 watt
D.
1 joule
Answer: Option A Answer: Option C
. .
58. How is power dissipated in a resistor? A.
by resistance
B.
by voltage
C.
by current
D.
by heat
62. Good insulators: A.
have few electrons in their outer shells
B.
have a large dielectric strength
C.
have a small breakdown voltage
D.
have many electrons in the nucleus
Answer: Option D Answer: Option B
.
XXIII - ALTERNATING CURRENT VS DIRECT CURRENT
1. What are the two main applications for ac? A. 59. Resistance in a circuit is:
direct, pulsating
B.
electric, magnetic
C.
power, information
D.
static, dynamic
.
5. What voltage will an ac voltmeter display? Answer: Option C
.
A.
rms
B.
average
C.
peak
D.
peak-to-peak
Answer: Option A 6. What is the peak value of a household appliance that uses a 230 V ac source?
2. The distance that a signal's energy can travel in the time it takes for one cycle to occur is called the signal's: A.
amplitude
B.
frequency
C.
wavelength
D.
period
A.
163 V
B.
230 V
C.
325 V
D.
480 V
Answer: Option C
Answer: Option C
.
.
3. One oscilloscope selector knob that allows the major and minor divisions of the graticule to be used to determine a signal amplitude value is called the: A.
time/cm control
B.
position control
C.
intensity control
D.
volts/cm control
7. What is the waveform period difference between the 60 Hz electricity used in this country and the 50 Hz used in Europe? A.
3 ms
B.
16 ms
C.
4 ms
D.
20 ms
Answer: Option A
Answer: Option D
.
.
4. If current varies periodically from zero to a maximum, back to zero, and then repeats, the signal is: A.
direct
B.
alternating
C.
pulsating
D.
repetitive
Answer: Option C
8. Test equipment selection enables the technician to both generate signals and: A.
change circuit conditions
B.
inject signals
C.
sense circuit conditions
D.
change signal frequencies
Answer: Option C
D.
9.42 V
Answer: Option C
.
. 9. Why is ac current transfer more effective than dc current transfer over long distances? A.
due to the height of power lines
B.
due to the use of ac generators
C.
due to step-up and step-down transformers reducing I2R losses
D.
due to very high voltages
13. A test equipment item that has the ability to produce either square, triangular, or sawtooth waveforms is called:
Answer: Option C
A.
a function generator
B.
a radio frequency generator
C.
an audio frequency generator
D.
a frequency meter or counter
Answer: Option A
.
. 10. A sine wave reaches maximum positive voltage at: A.
90°
B.
0°
C.
–90°
D.
360°
14. The current is flowing in what direction?
Answer: Option A 11. Which percentages of full-amplitude rise time are used for a pulse wave? A.
0 to 50 percent
B.
0 to 100 percent
C.
5 to 95 percent
D.
10 to 90 percent
Answer: Option D
A.
clockwise
B.
counterclockwise
C.
in both directions at the same time
D.
50% of the time clockwise and 50% of the time counterclockwise
Answer: Option D
.
. 12. What is the average value of a 12 V peak wave? A.
3.82 V
B.
4.24 V
C.
7.64 V
15. What does the CRT oscilloscope display? A.
voltage and period
B.
current and frequency
C.
rms voltage and current
D.
frequency and voltage
19. If a sine wave signal is 100 mV peak-to-peak, how many volts would be measured by a voltmeter?
Answer: Option A 16. Power companies supply ac, not dc, because:
A.
14.14 mV
B.
35.4 mV
A.
it is easier to transmit ac
C.
63.7 mV
B.
there is no longer a need for dc
D.
70.7 mV
C.
dc is more dangerous
D.
there are not enough batteries
Answer: Option B
Answer: Option A
.
. 20.
What term expresses the frequency of a rectangular wave?
17. If a waveform period is determined to be 10 microseconds in duration, what is the frequency of the signal? A.
100 Hz
B.
1000 Hz
C.
10 kHz
D.
100 kHz
A.
Hz
B.
period
C.
PRF
D.
PRT
Answer: Option C 21. AC effective voltage is named:
Answer: Option D
A.
average
B.
peak
C.
peak-to-peak
D.
root mean square
Answer: Option D .
.
18. The phase difference between sine waves of different frequencies is: A.
equal to their frequency differences
B.
the difference in their fixed time displacement
C.
the same throughout time
A.
159.0 mV
D.
constantly changing
B.
318.5 mV
C.
353.5 mV
D.
451.0 mV
Answer: Option B
.
22. If a voltmeter measures a sine wave as 500 mV, what would be its average value?
Answer: Option B
D.
low voltage to low voltage
. Answer: Option C
23. One adjustable knob on the oscilloscope that allows the trace to be aligned with a reference graticule is called the: A.
position control
B.
focus control
C.
intensity control
D.
volts/cm control
.
27. A rectangular wave that has a duty cycle of 50 percent could be called a:
Answer: Option A
A.
c wave
B.
sawtooth wave
C.
square wave
D.
triangle wave
. Answer: Option C
24. Signal comparisons may be most easily seen when using which item of test equipment?
.
A.
spectrum analyzer
B.
multimeter
C.
function generator
A.
positive ramps only
D.
dual trace oscilloscope
B.
negative ramps only
C.
positive and negative ramps of equal value
D.
positive and negative ramps of unequal value
28. A triangle wave consists of repeating:
Answer: Option D
Answer: Option C
.
. 25. The magnitude that an alternation varies from zero is called its:
26.
A.
altitude
B.
amplitude
C.
attitude
D.
polarity
Answer: Option B The power that is distributed from a power plant to your home is: A.
high voltage to high voltage
B.
low voltage to high voltage
C.
high voltage to low voltage
29. What is the name of a device used to directly measure the frequency of a periodic wave? A.
oscilloscope
B.
frequency meter or counter
C.
audio frequency generator
D.
radio frequency generator
Answer: Option B
.
C.
15.0 V
D.
21.2 V
Answer: Option B 30.
Which control should be moved to display more cycles of a signal on an oscilloscope? A.
horizontal position to left or right
B.
volts/cm to a smaller number
C.
vertical position to top or bottom
D.
time/cm to a higher setting
.
34. What is the peak-to-peak current value when an ammeter measures a 20 mA value?
Answer: Option D 31. What is the name of a device that converts sound waves to electrical waves? A.
an amplifier
B.
an antenna
C.
a filter
D.
a microphone
Answer: Option D
A.
14 mA
B.
28 mA
C.
40 mA
D.
57 mA
Answer: Option D
.
. 35. How long would it take to transmit an electromagnetic wave to a receiving antenna 1,000 miles away? 32. If the frequency of a radio wave is increased, then its wavelength will: A.
increase
B.
decrease
C.
remain the same
D.
cannot tell
Answer: Option B
.
33. What is the rms voltage value of an ac signal whose peak oscilloscope display uses 3 major divisions above the zero setting? (V/cm = 5) A.
5.3 V
B.
10.6 V
A.
5.38 ms
B.
10.8 ms
C.
53.8 ms
D.
108 ms
Answer: Option A 36. What is the waveform period of a square wave signal that horizontally covers 3 major divisions per cycle? (time/cm = 50 ms) A.
50 ms
B.
100 ms
C.
150 ms
D.
200 ms
Answer: Option C
.
40. What is the period of a 16 MHz sine wave? 37. A sine wave has: A.
four quadrants
B.
two alternations
C.
one period
D.
all of the above
A.
196 ns
B.
62.5 ns
C.
31.25 ns
D.
19.9 ns
Answer: Option B Answer: Option D XXIV - Semiconductor Principles
.
1. Intrinsic semiconductor material is characterized by a valence shell of how many electrons? A.
1
B.
2
C.
4
D.
6
38. What is the peak-to peak voltage of a 56 Vrms ac voltage? A.
158 V
B.
164 V
C.
82 V
D.
79 V
Answer: Option C
.
Answer: Option A 2. Ionization within a P-N junction causes a layer on each side of the barrier called the: .
39. One oscilloscope selector knob that allows the major and minor divisions of the graticule to be used to determine a waveform period is called a: A.
focus control
B.
time/cm control
C.
intensity control
D.
volts/cm control
Answer: Option B
.
A.
junction
B.
depletion region
C.
barrier voltage
D.
forward voltage
Answer: Option B
.
3. What is the most significant development in electronics since World War II? A.
the development of color TV
B.
the development of the diode
C.
the development of the transistor
D.
the development of the TRIAC
be: Answer: Option C
.
A.
holes
B.
dopants
C.
slower
D.
electrons
Answer: Option D
. 4. What causes the depletion region? A.
doping
B.
diffusion
C.
barrier potential
D.
ions
8. Elements with 1, 2, or 3 valence electrons usually make excellent: A.
conductors
B.
semiconductors
C.
insulators
D.
neutral
Answer: Option B Answer: Option A . .
5.
What is an energy gap? A.
the space between two orbital shells
B.
the energy equal to the energy acquired by an electron passing a 1 V electric field
C.
the energy band in which electrons can move freely
D.
an energy level at which an electron can exist
Answer: Option A 6. Silicon atoms combine into an orderly pattern called a: A.
covalent bond
B.
crystal
C.
semiconductor
D.
valence orbit
9. A commonly used pentavalent material is: A.
arsenic
B.
boron
C.
gallium
D.
neon
Answer: Option A
.
10. Which material may also be considered a semiconductor element? A.
carbon
B.
ceramic
C.
mica
D.
argon
Answer: Option B 11. .
7. In "n" type material, majority carriers would
Answer: Option A In "p" type material, minority carriers would be: A.
holes
B.
dopants
C.
slower
D.
electrons
Answer: Option D
. The purpose of p-type doping is to create an abundance of holes. In the case of silicon, a trivalent atom (typically from Group 13 of the periodic table, such as boron or aluminium) is substituted into the crystal lattice. The result is that one electron is missing from one of the four covalent bonds normal for the silicon lattice. Thus the dopant atom can accept an electron from a neighboring atom's covalent bond to complete the fourth bond. This is why such dopants are called acceptors. The dopant atom accepts an electron, causing the loss of half of one bond from the neighboring atom and resulting in the formation of a "hole". Each hole is associated with a nearby negatively charged dopant ion, and the semiconductor remains electrically neutral as a whole. However, once each hole has wandered away into the lattice, one proton in the atom at the hole's location will be "exposed" and no longer cancelled by an electron. This atom will have 3 electrons and 1 hole surrounding a particular nucleus with 4 protons. For this reason a hole behaves as a positive charge. When a sufficiently large number of acceptor atoms are added, the holes greatly outnumber thermal excited electrons. Thus, holes are the majority carriers, while electrons become minority carriers in p-type materials.
12. What can a semiconductor sense? A.
magnetism
B.
temperature
C.
pressure
D.
all of the above
14. Forward bias of a silicon P-N junction will produce a barrier voltage of approximately how many volts? A.
0.2
B.
0.3
C.
0.7
D.
0.8
Answer: Option C
.
15.
Which semiconductor material is made from coal ash? A.
germanium
B.
silicon
C.
tin
D.
carbon
Answer: Option A 16. When and who discovered that more than one transistor could be constructed on a single piece of semiconductor material: A.
1949, William Schockley
B.
1955, Walter Bratten
C.
1959, Robert Noyce
D.
1960, John Bardeen
Answer: Option D Answer: Option C . .
13. When an electron jumps from the valence shell to the conduction band, it leaves a gap. What is this gap called? A.
energy gap
B.
hole
C.
electron-hole pair
D.
recombination
Answer: Option B
17. When is a P-N junction formed? A.
in a depletion region
B.
in a large reverse biased region
C.
the point at which two opposite doped materials come together
D.
whenever there is a forward voltage drop
Answer: Option C
A.
1
B.
2
C.
3
D.
4
. Answer: Option D
.
18. A P-N junction mimics a closed switch when it: A.
has a low junction resistance
B.
is reverse biased
C.
cannot overcome its barrier voltage
D.
has a wide depletion region
22. What is a type of doping material? A.
extrinsic semiconductor material
B.
pentavalent material
C.
n-type semiconductor
D.
majority carriers
Answer: Option A Answer: Option B . .
19. Solid state devices were first manufactured during: A.
World War 2
B.
1904
C.
1907
D.
1960
23. Minority carriers are many times activated by: A.
heat
B.
pressure
C.
dopants
D.
forward bias
Answer: Option D Answer: Option A
. .
20. Electron pair bonding occurs when atoms: A.
lack electrons
B.
share holes
C.
lack holes
D.
share electrons
Answer: Option D 21. How many valence electrons are in every semiconductor material?
24. What is the voltage across R1 if the P-N junction is made of silicon?
A.
12 V
B.
11.7 V
C.
11.3 V
D.
0V
XXV- BIPOLAR JUNCTION TRANSISTORS (BJT)
1. When transistors are used in digital circuits they usually operate in the: Answer: Option C
.
A.
active region
B.
breakdown region
C.
saturation and cutoff regions
D.
linear region
Answer: Option C 25. If conductance increases as temperature increases, this is known as a: A.
positive coefficient
B.
negative current flow
C.
negative coefficient
D.
positive resistance
.
2. Three different Q points are shown on a dc load line. The upper Q point represents the: Answer: Option C
A negative temperature coefficient (NTC) occurs when the thermal conductivity of a material rises with increasing temperature, typically in a defined temperature range. 26. Which of the following cannot actually move? A.
majority carriers
B.
ions
C.
holes
D.
free electrons
Answer: Option B
A.
minimum current gain
B.
intermediate current gain
C.
maximum current gain
D.
cutoff point
Answer: Option C
.
3. A transistor has a of 250 and a base current, IB, of 20 A. The collector current, IC, equals:
.
27. What electrical characteristic of intrinsic semiconductor material is controlled by the addition of impurities? A.
conductivity
B.
resistance
C.
power
D.
all of the above
Answer: Option A
A.
500
B.
5 mA
C.
50 mA
D.
5A
A
Answer: Option B
.
4. A current ratio of IC/IE is usually less than one and is called: A.
beta
B.
theta
C.
alpha
D.
omega
8. To operate properly, a transistor's base-emitter junction must be forward biased with reverse bias applied to which junction?
Answer: Option C
.
A.
collector-emitter
B.
base-collector
C.
base-emitter
D.
collector-base
Answer: Option D
. 5. With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be: A.
open
B.
infinite
C.
low resistance
A.
saturation and cutoff
D.
high resistance
B.
the operating point
C.
the power curve
D.
the amplification factor
9. The ends of a load line drawn on a family of curves determine:
Answer: Option C 6. In a C-E configuration, an emitter resistor is used for: A.
stabilization
B.
ac signal bypass
C.
collector bias
D.
higher gain
Answer: Option A
.
Answer: Option A
10.
If VCC = +18 V, voltage-divider resistor R1 is 4.7 k , and R2 is 1500 , what is the base bias voltage?
.
7. Voltage-divider bias provides: A.
an unstable Q point
B.
a stable Q point
C.
a Q point that easily varies with changes in the transistor's current gain
D.
a Q point that is stable and easily varies with changes in the transistor’s current gain
A.
8.70 V
B.
4.35 V
C.
2.90 V
D.
0.7 V
Answer: Option B 11. The C-B configuration is used to provide which type of gain? A.
voltage
B.
current
C.
resistance
D.
power
Answer: Option B Answer: Option A
.
. Answer: Option A 16. A collector characteristic curve is a graph showing: 12. The Q point on a load line may be used to determine: A.
VC
B.
VCC
C.
VB
D.
IC
A.
emitter current (IE) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
B.
collector current (IC) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
C.
collector current (IC) versus collector-emitter voltage (VC) with (VBB) base bias voltage held constant
D.
collector current (IC) versus collector-emitter voltage (VCC) with (VBB) base bias voltage held constant
Answer: Option C
.
13. A transistor may be used as a switching device or as a: A.
fixed resistor
B.
tuning device
C.
rectifier
D.
variable resistor
Answer: Option B
.
Answer: Option D
17. With low-power transistor packages, the base terminal is usually the:
.
14. If an input signal ranges from 20–40 A (microamps), with an output signal ranging from .5–1.5 mA (milliamps), what is the ac beta? A.
0.05
B.
20
C.
50
D.
500
A.
tab end
B.
middle
C.
right end
D.
stud mount
Answer: Option B
.
Answer: Option C 18. When a silicon diode is forward biased, what is VBE for a C-E configuration? .
15. Which is beta's current ratio? A.
IC/IB
B.
IC/IE
C.
IB/IE
D.
IE/IB
A.
voltage-divider bias
B.
0.4 V
C.
0.7 V
D.
emitter voltage
Answer: Option C
. .
23. Most of the electrons in the base of an NPN transistor flow: 19. What is the current gain for a common-base configuration where IE = 4.2 mA and IC= 4.0 mA?
A.
out of the base lead
A.
16.80
B.
1.05
B.
into the collector
C.
0.20
D.
0.95
C.
into the emitter
D.
into the base supply
Answer: Option D Answer: Option B
. .
20.
With a PNP circuit, the most positive voltage is probably: A.
ground
B.
VC
C.
VBE
D.
VCC
24. In a transistor, collector current is controlled by:
Answer: Option A 21. If a 2 mV signal produces a 2 V output, what is the voltage gain? A.
0.001
B.
0.004
C.
100
D.
1000
Answer: Option D
A.
collector voltage
B.
base current
C.
collector resistance
D.
all of the above
Answer: Option B
.
. 25. Total emitter current is:
22. The symbol hfe is the same as: A.
A.
IE – IC
B.
IC + IE
C.
IB + IC
D.
IB – IC
B. C.
hi-fi
D.
Answer: Option A
Answer: Option C 26. Often a common-collector will be the last stage before the load; the main function(s) of this stage is to: A.
provide voltage gain
B.
provide phase inversion
C.
provide a high-frequency path to improve the frequency response
D.
Answer: Option D
buffer the voltage amplifiers from the low-resistance load and provide impedance matching for maximum power transfer
.
Answer: Option D
30.
Which is the higher gain provided by a C-E configuration?
.
27. For a C-C configuration to operate properly, the collector-base junction should be reverse biased, while forward bias should be applied to which junction? A.
collector-emitter
B.
base-emitter
C.
collector-base
D.
cathode-anode
A.
voltage
B.
current
C.
resistance
D.
power
Answer: Option D 31. What is the collector current for a C-E configuration with a beta of 100 and a base current of 30 A?
Answer: Option A
A.
30
A
B.
.3
A
C.
3 mA
D.
3 MA
. Answer: Option C
XXVI - Field Effect Transistors (FET) 28. The input/output relationship of the common-collector and common-base amplifiers is: A.
270 degrees
B.
180 degrees
C.
90 degrees
D.
0 degrees
1. Junction Field Effect Transistors (JFET) contain how many diodes? A.
4
B.
3
C.
2
D.
1
Answer: Option D Answer: Option D . .
2. When an input delta of 2 V produces a transconductance of 1.5 mS, what is the drain current delta? 29. If a transistor operates at the middle of the dc load line, a decrease in the current gain will move the Q point:
A.
666 mA
B.
3 mA
A.
off the load line
C.
0.75 mA
B.
nowhere
D.
0.5 mA
C.
up
D.
down
Answer: Option B
500 .
. What is wrong?
A.
short D to S
B.
open G to D
C.
open D to SS
D.
nothing
3. When not in use, MOSFET pins are kept at the same potential through the use of: A.
shipping foil
B.
nonconductive foam
C.
conductive foam
D.
a wrist strap
Answer: Option D
.
Answer: Option C 7. In the constant-current region, how will the IDS change in an n-channel JFET? .
4. D-MOSFETs are sometimes used in series to construct a cascode high-frequency amplifier to overcome the loss of: A.
low output impedance
B.
capacitive reactance
C.
high input impedance
D.
inductive reactance
A.
As VGS decreases ID decreases.
B.
As VGS increases ID increases.
C.
As VGS decreases ID remains constant.
D.
As VGS increases ID remains constant.
Answer: Option A
.
Answer: Option C 8. A MOSFET has how many terminals? .
5.
A "U" shaped, opposite-polarity material built near a JFET-channel center is called the: A.
gate
B.
block
C.
drain
D.
heat sink
Answer: Option A 6. When testing an n-channel D-MOSFET, resistance G to D = , resistance G to S = , resistance D to SS = and 500 , depending on the polarity of the ohmmeter, and resistance D to S =
A.
2 or 3
B.
3
C.
4
D.
3 or 4
Answer: Option D
.
9. IDSS can be defined as: A.
the minimum possible drain current
B.
the maximum possible current
13. With the E-MOSFET, when gate input voltage is zero, drain current is:
with VGS held at –4 V C.
the maximum possible current with VGS held at 0 V
D.
the maximum drain current with the source shorted
A.
at saturation
B.
zero
C.
IDSS
D.
widening the channel
Answer: Option C Answer: Option B . .
10. What is the input impedance of a common-gate configured JFET? 14. With a 30-volt VDD, and an 8-kilohm drain resistor, what is the E-MOSFET Q point voltage, with ID = 3 mA?
A.
very low
B.
low
A.
6V
C.
high
B.
10 V
D.
very high
C.
24 V
D.
30 V
Answer: Option A 11. JFET terminal "legs" are connections to the drain, the gate, and the: A.
channel
B.
source
C.
substrate
D.
cathode
Answer: Option A
. Answer: Option B
.
12. A very simple bias for a D-MOSFET is called: A.
self biasing
B.
gate biasing
C.
zero biasing
D.
voltage-divider biasing
Answer: Option C
15. When an input signal reduces the channel size, the process is called: A.
enhancement
B.
substrate connecting
C.
gate charge
D.
depletion
Answer: Option D 16. Which JFET configuration would connect a highresistance signal source to a low-resistance load? A.
source follower
B.
common-source
C.
common-drain
D.
common-gate
. Answer: Option A
20. When is a vertical channel E-MOSFET used? .
A.
for high frequencies
B.
for high voltages
C.
for high currents
D.
for high resistances
17. How will electrons flow through a p-channel JFET? A.
from source to drain
B.
from source to gate
C.
from drain to gate
D.
from drain to source
Answer: Option C 21. When the JFET is no longer able to control the current, this point is called the:
Answer: Option D
A.
breakdown region
B.
depletion region
C.
saturation point
D.
pinch-off region
Answer: Option A
.
. 18. When VGS = 0 V, a JFET is: A.
saturated
B.
an analog device
C.
an open switch
D.
cut off
22. With a JFET, a ratio of output current change against an input voltage change is called: A.
transconductance
B.
siemens
C.
resistivity
D.
gain
Answer: Option A Answer: Option A
. .
19. When applied input voltage varies the resistance of a channel, the result is called: A.
saturization
B.
polarization
C.
cutoff
D.
field effect
23. Which type of JFET bias requires a negative supply voltage? A.
feedback
B.
source
C.
gate
D.
voltage divider
Answer: Option D Answer: Option C
. .
than 1 D.
no voltage gain
24. How will a D-MOSFET input impedance change with signal frequency? A.
As frequency increases input impedance increases.
B.
As frequency increases input impedance is constant.
C.
As frequency decreases input impedance increases.
D.
As frequency decreases input impedance is constant.
Answer: Option A
.
28. Using voltage-divider biasing, what is the voltage at the gate VGS? Answer: Option C
.
25. The type of bias most often used with E-MOSFET circuits is: A.
constant current
B.
drain-feedback
C.
voltage-divider
D.
zero biasing
Answer: Option B 26. The transconductance curve of a JFET is a graph of: A.
IS versus VDS
B.
IC versus VCE
C.
ID versus VGS
D.
ID × RDS
Answer: Option C
A.
5.2 V
B.
4.2 V
C.
3.2 V
D.
2.2 V
Answer: Option A
.
. 29. The overall input capacitance of a dual-gate D-MOSFET is lower because the devices are usually connected:
27. The common-source JFET amplifier has: A.
a very high input impedance and a relatively low voltage gain
B.
a high input impedance and a very high voltage gain
C.
a high input impedance and a voltage gain less
A.
in parallel
B.
with separate insulation
C.
with separate inputs
D.
in series
further increases in ID
Answer: Option D D. .
the value of VDS at which further increases in VGS will cause no further increases in ID
Answer: Option A
30.
What is the transconductance of an FET when ID = 1 mA and VGS = 1 V?
XXVII - THYRISTORS AND TRANDUCERS
A.
1 kS
B.
1 mS
A.
can trigger only on positive gate voltages
C.
1k
B.
can trigger only on negative gate voltages
D.
1m
C.
cannot be triggered with gate voltages
D.
can be triggered by either a positive or a negative gate voltage
1. A TRIAC:
Answer: Option B In an n-channel JFET, what will happen at the pinch-off voltage?
A.
the value of VDS at which further increases in VDS will cause no further increase in ID
B.
the value of VGS at which further decreases in VGS will cause no further increases in ID
C.
the value of VDG at which further decreases in VDG will cause no further increases in ID
D.
the value of VDS at which further increases in VGS will cause no further increases in ID
Answer: Option D
.
2. When checking a good SCR or TRIAC with an ohmmeter it will: A.
show high resistance in both directions
B.
show low resistance with positive on anode and negative on cathode, and high resistance when reversed
C.
show high resistance with negative on anode and positive on cathode, and low resistance when reversed
D.
show low resistance in both directions
Answer: Option A 31. Which component is considered to be an "OFF" device? A.
transistor
B.
JFET
C.
D-MOSFET
D.
E-MOSFET
Answer: Option D Answer: Option A
. .
32. In an n-channel JFET, what will happen at the pinch-off voltage? A.
the value of VDS at which further increases in VDS will cause no further increase in ID
B.
the value of VGS at which further decreases in VGS will cause no further increases in ID
C.
the value of VDG at which further decreases in VDG will cause no
3. What does a hall effect sensor sense? A.
temperature
B.
moisture
C.
magnetic fields
D.
pressure
Answer: Option C
.
. 7. The only way to close an SCR is with:
4. What causes the piezoelectric effect?
A.
a trigger input applied to the gate
B.
forward breakover voltage
A.
heat or dissimilar metals
C.
low-current dropout
B.
pressure on a crystal
D.
valley voltage
C.
water running on iron
D.
a magnetic field
Answer: Option B
Answer: Option B
.
. 8. What is an SCR?
5.
Which is the DIAC?
A.
A.
a PNPN thyristor with 3 terminals
B.
a PNPN thyristor with 4 terminals
C.
a PNP thyristor with 3 terminals
D.
an NPN thyristor with 3 terminals
B.
Answer: Option A C. . D.
9. The only way to close an SCR is with: 6. A UJT has:
Answer: Option A
A.
two base leads
B.
one emitter lead
C.
two emitter leads and one base lead
D.
one emitter lead and two base leads
A.
a trigger input applied to the gate
B.
forward breakover voltage
C.
low-current dropout
D.
valley voltage
Answer: Option B
Answer: Option D .
Answer: Option D
10. What type of application would use a photovoltaic cell? A.
an automobile horn
B.
a TI 92 calculator
C.
a magnetic field detector
D.
a remote power source
.
13. Once a DIAC is conducting, the only way to turn it off is with:
Answer: Option D 11. Which is the seven-segment display?
A.
A.
a positive gate voltage
B.
a negative gate voltage
C.
low-current dropout
D.
breakover
Answer: Option C
.
B. 14. Which is the TRIAC?
A.
C.
B. D.
C. Answer: Option A D. .
Answer: Option D
12. The smallest amount of current that the cathode-anode can have, and still sustain conduction of an SCR is called the: A.
maximum forward current
B.
maximum forward gate current
C.
holding current
D.
reverse gate leakage current
.
15.
The DIAC is a: A.
transistor
B.
unidirectional device
C.
three-layer device
D.
bidirectional device
Answer: Option D 16. What type of application would use an injection laser diode? A.
a 10BASE-T Ethernet
B.
a liquid crystal display
C.
a fiber optic transmission line
D.
a good flashlight
Answer: Option C
A.
UJT thyristor
B.
FET device
C.
TRIAC
D.
SCR
Answer: Option A
vetilog
D.
sine wave
Answer: Option B
.
2. Which of the following characterizes an analog quantity?
.
17. The PUT (programmable unijunction transistor) is actually a type of:
C.
A.
Discrete levels represent changes in a quantity.
B.
Its values follow a logarithmic response curve.
C.
It can be described with a finite number of steps.
D.
It has a continuous set of values over a given range.
Answer: Option D
.
3. ASCII stands for: A.
American Serial Communication Interface
B.
Additive Signal Coupling Interface
C.
American Standard Code for Information Interchange
D.
none of the above
.
18. A transducer's function is to: A.
transmit electrical energy
B.
convert energy
C.
produce mechanical energy
D.
prevent current flow
Answer: Option B
XVIII - ANALOG TO DIGITAL
1. The two basic types of signals are analog and: A.
digilog
B.
digital
Answer: Option C
.
4. Which type of signal is represented by discrete values? A.
noisy signal
B.
nonlinear
C.
analog
D.
digital
Answer: Option D Answer: Option C . .
5. A data conversion system may be used to interface a digital computer system to: A.
an analog output device
B.
a digital output device
C.
an analog input device
D.
a digital printer
4. The number of bits used to store a BCD digit is: A.
8
B.
4
C.
1
D.
2
Answer: Option B Answer: Option A . XXIX - NUMBER SYSTEMS AND CODES
1. Base 10 refers to which number system? A.
binary coded decimal
B.
decimal
A.
sample and hold the output of the binary counter during the c
C.
octal
B.
stabilize the ADCs threshold voltage during the conversion pro
D.
hexadecimal
C.
stabilize the input analog signal during the conversion process
D.
sample and hold the ADC staircase waveform during the conv
5. Sample-and-hold circuits in ADCs are designed to:
Answer: Option B 6.
Answer: Option C
.
2. Convert the decimal number 151.75 to binary. A.
10000111.11
B.
11010011.01
C.
00111100.00
D.
10010111.11
Answer: Option D
.
7. What is the difference between binary coding and binary coded decimal?
3. Convert the binary number 1011010 to hexadecimal. A.
5B
B.
5F
C.
5A
D.
5C
A.
Binary coding is pure binary.
B.
BCD is pure binary.
C.
Binary coding has a decimal format.
D.
BCD has no decimal format.
Answer: Option A 12. 3428 is the decimal value for which of the following binary coded decimal (BCD) groupings? .
A.
11010001001000
B.
11010000101000
C.
011010010000010
D.
110100001101010
Answer: Option B 8. Convert the binary number 1001.0010 to decimal. A.
125
B.
12.5
C.
90.125
D.
9.125
.
Answer: Option D 13. What is the result when a decimal 5238 is converted to base 16? .
201
B.
2001
C.
20
D.
210
327.375
B.
12166
C.
1388
D.
1476
Answer: Option D
9. Convert 110010012 (binary) to decimal. A.
A.
XXX - LOGIC GATES
1. The output will be a LOW for any case when one or more inputs are zero in a(n):
Answer: Option A
.
10. What is the decimal value of the hexadecimal number 777? A.
191
B.
1911
C.
19
D.
19111
A.
OR gate
B.
NOT gate
C.
AND gate
D.
NAND gate
Answer: Option C
.
Answer: Option B 11. What is the resultant binary of the decimal problem 49 +1=? A.
01010101
B.
00110101
C.
00110010
D.
00110001
2. If a signal passing through a gate is inhibited by sending a low into one of the inputs, and the output is HIGH, the gate is a(n): A.
AND
B.
NAND
C.
NOR
D.
OR
Answer: Option C Answer: Option B .
.
Answer: Option C
. 3. A single transistor can be used to build which of the following digital logic gates? A.
AND gates
B.
OR gates
C.
NOT gates
D.
NAND gates
7. How many truth table entries are necessary for a fourinput circuit? A.
4
B.
8
C.
12
D.
16
Answer: Option C Answer: Option D
. .
4. The logic gate that will have HIGH or "1" at its output when any one of its inputs is HIGH is a(n):
8. A NAND gate has:
A.
OR gate
A.
LOW inputs and a LOW output
B.
AND gate
B.
HIGH inputs and a HIGH output
C.
NOR gate
C.
LOW inputs and a HIGH output
D.
NOT gate
D.
None of the these
Answer: Option A
Answer: Option C
.
.
5. How many NAND circuits are contained in a 7400 NAND IC?
9. The basic logic gate whose output is the complement of the input is the:
A.
1
B.
2
A.
OR gate
C.
4
D.
8
B.
AND gate
C.
INVERTER gate
D.
comparator
Answer: Option C 6. Exclusive-OR (XOR) logic gates can be constructed from what other logic gates? A.
OR gates only
B.
AND gates and NOT gates
C.
AND gates, OR gates, and NOT gates
D.
OR gates and NOT gates
Answer: Option C
.
10. What input values will cause an AND logic gate to produce a HIGH output? A.
At least one input is HIGH.
B.
At least one input is LOW.
C.
All inputs are HIGH.
D.
All inputs are LOW.
Answer: Option A
.
4. The observation that a bubbled input OR gate is interchangeable with a bubbled output AND gate is referred to as:
Answer: Option C
XXXI - LOGIC CIRCUIT SIMPLIFICATION
1. Which statement below best describes a Karnaugh map? A.
It is simply a rearranged truth table.
B.
The Karnaugh map eliminates the need for using NAND and NOR gates.
C.
Variable complements can be eliminated by using Karnaugh maps.
D.
A Karnaugh map can be used to replace Boolean rules.
A.
a Karnaugh map
B.
DeMorgan's second theorem
C.
the commutative law of addition
D.
the associative law of multiplication
Answer: Option B
.
Answer: Option A
5.
The systematic reduction of logic circuits is accomplished by:
.
2. Which of the examples below expresses the commutative law of multiplication? A.
A+B=B+A
B.
A•B=B+A
C.
A • (B • C) = (A • B) • C
D.
A•B=B•A
A.
symbolic reduction
B.
TTL logic
C.
using Boolean algebra
D.
using a truth table
Answer: Option C 6. Logically, the output of a NOR gate would have the same Boolean expression as a(n): A.
NAND gate immediately followed by an INVERTER
B.
OR gate immediately followed by an INVERTER
C.
AND gate immediately followed by an INVERTER
D.
NOR gate immediately followed by an INVERTER
Answer: Option D
.
Answer: Option B 3.
The Boolean expression equivalent to what single gate?
is logically
A.
NAND
B.
NOR
C.
AND
D.
OR
.
7. Which of the examples below expresses the distributive law of Boolean algebra? A.
A • (B • C) = (A • B) + C
B.
A + (B + C) = (A • B) + (A • C)
C.
A • (B + C) = (A • B) + (A • C)
D.
10. The commutative law of addition and multiplication indicates that:
(A + B) + C = A + (B + C)
A.
the way we OR or AND two variables is unimportant because the result is the same
B.
we can group variables in an AND or in an OR any way we want
C.
an expression can be expanded by multiplying term by term just the same as in ordinary algebra
D.
the factoring of Boolean expressions requires the multiplication of product terms that contain like variables
Answer: Option C
.
8. Which output expression might indicate a product-of-sums circuit construction? A.
Answer: Option A
11. Which of the following expressions is in the sum-ofproducts (SOP) form?
B. C.
A.
Y = (A + B)(C + D)
B.
Y = AB(CD)
C.
D.
D. Answer: Option D Answer: Option C .
XXXII - STANDARD LOGIC DEVICES (SLD)
9. One of DeMorgan's theorems states
1. A digital logic device used as a buffer should have what input/output characteristics?
that . Simply stated, this means that logically there is no difference between: A. B.
a NAND gate and an AND gate with a bubbled output a NOR gate and an AND gate with a bubbled output
C.
a NOR gate and a NAND gate with a bubbled output
D.
a NAND gate and an OR gate with a bubbled output
Answer: Option A
A.
high input impedance and high output impedance
B.
low input impedance and high output impedance
C.
low input impedance and low output impedance
D.
high input impedance and low output impedance
Answer: Option D
.
. 2. What is the standard TTL noise margin?
A.
5.0 V
B.
0.2 V
C.
0.8 V
D.
0.4 V
D.
DIP
Answer: Option A 6. The problem of interfacing IC logic families that have different supply voltages (VCCs) can be solved by using a:
Answer: Option D
.
A.
level-shifter
B.
tri-state shifter
C.
translator
D.
level-shifter or translator
Answer: Option D 3. The range of a valid LOW input is: A.
0.0 V to 0.4 V
B.
0.4 V to 0.8 V
C.
0.4 V to 1.8 V
D.
0.4 V to 2.4 V
.
7. Ten TTL loads per TTL driver is known as:
Answer: Option B
.
A.
noise immunity
B.
power dissipation
C.
fanout
D.
propagation delay
Answer: Option C 4. When an IC has two rows of parallel connecting pins, the device is referred to as: A.
a QFP
B.
a DIP
C.
a phase splitter
D.
CMOS
.
8. Which of the following summarizes the important features of emitter-coupled logic (ECL)?
Answer: Option B A.
negative voltage operation, high speed, and high power consumption
B.
good noise immunity, negative logic, high frequency capability, low power dissipation, and short propagation time
C.
slow propagation time, high frequency response, low power consumption, and high output voltage swings
D.
poor noise immunity, positive supply voltage operation, good low-frequency operation, and low power
.
5.
Which digital IC package type makes the most efficient use of printed circuit board space? A.
SMT
B.
TO can
C.
flat pack
Answer: Option A
12. A TTL totem pole circuit is designed so that the output transistors are:
.
9. What quantities must be compatible when interfacing two different logic families? A.
only the currents
B.
both the voltages and the currents
C.
only the voltages
D.
both the power dissipation and the impedance
A.
always on together
B.
providing phase splitting
C.
providing voltage regulation
D.
never on together
Answer: Option D
.
13. The time needed for an output to change as the result of an input change is known as:
Answer: Option B
.
A.
noise immunity
B.
fanout
C.
propagation delay
D.
rise time
Answer: Option C 10. CMOS logic is probably the best allaround circuitry because of its: A.
packing density
B.
low power consumption
C.
very high noise immunity
D.
low power consumption and very high noise immunity
Answer: Option D 11. Low power consumption achieved by CMOS circuits is due to which construction characteristic? A.
complementary pairs
B.
connecting pads
C.
DIP packages
D.
small-scale integration
Answer: Option A
.
XXXIII - PROGRAMMABLE LOGIC DEVICES (PLD)
1. Which type of PLD should be used to program basic logic functions? A.
PLA
B.
PAL
C.
CPLD
D.
SLD
Answer: Option B
.
2. The content of a simple programmable logic device (PLD) consists of: A.
fuse-link arrays
B.
thousands of basic logic gates
C.
advanced sequential logic functions
D.
thousands of basic logic gates and advanced sequential logic functions
B.
the PAL has a programmable OR plane and a programmable AND plane, while the PLA only has a programmable AND plane
C.
the PAL has more possible product terms than the PLA
D.
PALs and PLAs are the same thing.
Answer: Option D
.
Answer: Option A 3. Once a PAL has been programmed:
XXXIV - TESTING AND TROUBLESHOOTING
A.
it cannot be reprogrammed.
B.
its outputs are only active HIGHs
C.
its outputs are only active LOWs
D.
its logic capacity is lost
1. A series of gradually decreasing sine wave oscillations is called: A.
ringing
B.
slew
C.
overshooting
D.
undershooting
Answer: Option A
Answer: Option A
.
.
4. The complex programmable logic device (CPLD) contains several PLD blocks and:
2. The determination of a digital signal's frequency and waveshape is best accomplished with which test equipment?
A.
field-programmable switches
A.
an oscilloscope
B.
AND/OR arrays
B.
a multimeter
C.
a global interconnection matrix
C.
a spectrum analyzer
D.
a language compiler
D.
a frequency generator
Answer: Option C
Answer: Option A
.
.
5. PLAs, CPLDs, and FPGAs are all which type of device? A.
SLD
B.
PLD
C.
EPROM
D.
SRAM
Answer: Option B
6. The difference between a PLA and a PAL is: A.
the PLA has a programmable OR plane and a programmable AND plane, while the PAL only has a programmable AND plane
3. A logic probe is placed on the output of a gate and the display indicator is dim. A logic pulser is used on each of the input terminals, but the output indication does not change. What is wrong? A.
The dim indication on the logic probe indicates that the supply voltage is probably low.
B.
The output of the gate appears to be open.
C.
The LOW indication is the result of a bad ground connection on the logic probe.
D.
The gate is a tri-state device.
Answer: Option B A. Duty Cycle = . B. Duty Cycle =
C. 4. A +5 V PCB power source that has been "pulled down" to a +3.4 V level may be due to: A.
a circuit open
B.
a faulty regulator
C.
the half-split method
D.
a circuit short
Answer: Option D
Duty Cycle =
D. Duty Cycle =
Answer: Option A
.
. 8. What is the next step after discovering a faulty gate within an IC?
5.
Measurement of pulse width should be taken at a 50% mean of the:
A.
repair the gate
B.
resolder the tracks
A.
overshoot and undershoot
C.
replace the IC involved
B.
rise and fall
D.
recheck the power source
C.
damping and ringing
D.
leading and trailing amplitude
Answer: Option B 6. Which test equipment best allows a comparison between input and output signals? A.
an oscilloscope
B.
a logic probe
C.
a spectrum analyzer
D.
a multitrace oscilloscope
Answer: Option C
.
9. The use of a multimeter with digital circuits allows the measurement of:
Answer: Option D
A.
pulse width
B.
voltage or resistance
C.
current
D.
pulse trains
. Answer: Option B
7. The duty cycle of a pulse is determined by which formula?
.
10. The use of triggered sweep when using an oscilloscope provides more accuracy in which area?
2. Most demultiplexers facilitate which of the following?
A.
frequency
A.
decimal to hexadecimal
B.
amplitude
B.
single input, multiple outputs
C.
graticule activity
C.
ac to dc
D.
timing
D.
odd parity to even parity
Answer: Option D 11. The time needed for a pulse to increase from 10% to 90% of its amplitude defines: A.
pulse width
B.
propagation delay
C.
rise time
D.
duty cycle
Answer: Option B
.
3. One application of a digital multiplexer is to facilitate: Answer: Option C
.
A.
code conversion
B.
parity checking
C.
parallel-to-serial data conversion
D.
data generation
Answer: Option C 12. Which device would best aid in shorted track detection? A.
multimeter
B.
current tracer
C.
logic pulser
D.
oscilloscope
.
4. Select one of the following statements that best describes the parity method of error detection:
Answer: Option B
XXXV - COMBINATIONAL LOGIC CIRCUITS
1. How many inputs are required for a 1-of-10 BCD decoder? A.
4
B.
8
C.
10
D.
1
Answer: Option A
.
A.
Parity checking is best suited for detecting single-bit errors in transmitted codes.
B.
Parity checking is best suited for detecting double-bit errors that occur during the transmission of codes from one location to another.
C.
Parity checking is not suitable for detecting single-bit errors in transmitted codes.
D.
Parity checking is capable of detecting and correcting errors in transmitted codes.
Answer: Option A
.
5.
A multiplexed display: A.
accepts data inputs from one line and passes this data to multiple output lines
B.
uses one display to present two or more pieces of information
C.
accepts data inputs from multiple lines and passes this data to multiple output lines
D.
accepts data inputs from several lines and multiplexes this input data to four BCD lines
Answer: Option B 6. When two or more inputs are active simultaneously, the process is called:
C.
A = B and if A > B or A < b
D.
A
B and if A < b or a > B
Answer: Option C
.
9. A circuit that responds to a specific set of signals to produce a related digital signal output is called a(n): A.
BCD matrix
A.
first-in, first-out processing
B.
display driver
B.
priority encoding
C.
encoder
C.
ripple blanking
D.
decoder
D.
priority decoding Answer: Option C
Answer: Option B . .
10. Which digital system translates coded characters into a more intelligible form? 7. Which type of decoder will select one of sixteen outputs, depending on the 4-bit binary input value? A.
hexadecimal
B.
dual octal outputs
C.
binary-to-hexadecimal
D.
hexadecimal-to-binary
11.
A.
encoder
B.
display
C.
counter
D.
decoder
Answer: Option D A basic multiplexer principle can be demonstrated through the use of a:
Answer: Option A
A.
single-pole relay
B.
DPDT switch
C.
rotary switch
D.
linear stepper
. Answer: Option C
8. A magnitude comparator determines: A.
A
B and if A
B.
A
B and if A > B or A < b
.
B or A >> B
12. In a BCD-to-seven-segment converter, why must a
code converter be utilized? A.
No conversion is necessary.
B.
to convert the 4-bit BCD into gray code
C.
to convert the 4-bit BCD into 10-bit code
D.
to convert the 4-bit BCD into 7-bit code
D.
cross coupling
Answer: Option D
. Answer: Option D
XXXVI - FLIP-FLOPS AND TIMERS 4. The 555 timer can be used in which of the following configurations? 1. Which of the following is correct for a gated D-type flipflop? A.
The Q output is either SET or RESET as soon as the D input goes HIGH or LOW.
B.
The output complement follows the input when enabled.
C.
Only one of the inputs can be HIGH at a time.
D.
The output toggles if one of the inputs is held HIGH.
Answer: Option A
A.
astable, monostable
B.
monostable, bistable
C.
astable, toggled
D.
bistable, tristable
Answer: Option A
.
. 5. A basic S-R flip-flop can be constructed by crosscoupling which basic logic gates?
2. When both inputs of a J-K flip-flop cycle, the output will:
A.
AND or OR gates
B.
XOR or XNOR gates
A.
be invalid
C.
NOR or NAND gates
B.
not change
D.
AND or NOR gates
C.
change
D.
toggle
Answer: Option C 6. One example of the use of an S-R flip-flop is as a(n):
Answer: Option B
.
A.
transition pulse generator
B.
astable oscillator
C.
racer
D.
switch debouncer
Answer: Option D
3. Latches constructed with NOR and NAND gates tend to remain in the latched condition due to which configuration feature? A.
asynchronous operation
B.
low input voltages
C.
gate impedance
.
7. If both inputs of an S-R NAND latch are LOW, what will
happen to the output?
10. What is another name for a one-shot?
A.
The output would become unpredictable.
A.
monostable
B.
bistable
B.
The output will toggle.
C.
astable
D.
tristable
C.
The output will reset.
D.
No change will occur in the output.
Answer: Option A 11. The truth table for an S-R flip-flop has how many VALID entries?
Answer: Option A
.
A.
3
B.
1
C.
4
D.
2
Answer: Option A
. 8. The equation for the output frequency of a 555 timer operating in the astable mode
is: . What value of C1 will be required if R1 = 1 k , and f = 1 kHz? A.
0.33
F
B.
0.48
F
C.
480
D.
33 nF
, R2 = 1 k
12. What is the significance of the J and K terminals on the J-K flip-flop? A.
There is no known significance in their designations.
B.
The J represents "jump," which is how the Q output reacts whenever the clock goes HIGH and the J input is also HIGH.
C.
The letters represent the initials of Johnson and King, the co-inventors of the J-K flip-flop.
D.
All of the other letters of the alphabet are already in use.
F
Answer: Option B
Answer: Option A .
.
9. An astable multivibrator is a circuit that: A.
has two stable states
B.
is free-running
C.
produces a continuous output signal
D.
is free-running and produces a continuous output signal
13. Which of the following describes the operation of a positive edge-triggered D-type flip-flop? A.
If both inputs are HIGH, the output will toggle.
B.
The output will follow the input on the leading edge of the clock.
C.
When both inputs are LOW, an invalid state exists.
D.
The input is toggled into the flip-flop on the leading edge of the clock and is passed to the output on the trailing edge of the clock.
Answer: Option C
. Answer: Option B
number in one bit at a time and shift all the stored bits out one bit at a time? .
14. What is one disadvantage of an S-R flip-flop? A.
It has no Enable input.
B.
It has a RACE condition.
C.
It has no clock input.
D.
It has only a single output.
Answer: Option B
B.
all flip-flops and gates
C.
the flip-flops only with gates
D.
only circuit gates
B.
SISO
C.
SIPO
D.
PISO
.
4. Synchronous counters eliminate the delay problems encountered with asynchronous (ripple) counters because the:
1. A ripple counter's speed is limited by the propagation delay of: each flip-flop
PIPO
Answer: Option B
XXXVII - SEQUENTIAL LOGIC CIRCUITS
A.
A.
A.
input clock pulses are applied only to the first and last stages
B.
input clock pulses are applied only to the last stage
C.
input clock pulses are not used to activate any of the counter stages
D.
input clock pulses are applied simultaneously to each stage
Answer: Option D Answer: Option A . .
5. One of the major drawbacks to the use of asynchronous counters is that: 2. To operate correctly, starting a ring counter requires: A.
clearing all the flip-flops
B.
presetting one flip-flop and clearing all the others
C.
clearing one flip-flop and presetting all the others
D.
presetting all the flip-flops
A.
low-frequency applications are limited because of internal propagation delays
B.
high-frequency applications are limited because of internal propagation delays
C.
Asynchronous counters do not have major drawbacks and are suitable for use in high- and low-frequency counting applications.
D.
Asynchronous counters do not have propagation delays, which limits their use in high-frequency applications.
Answer: Option B
.
3. What type of register would shift a complete binary
Answer: Option B 6. Which type of device may be used to interface a parallel data format with external equipment's serial format? A.
key matrix
B.
UART
C.
memory chip
D.
serial-in, parallel-out
Answer: Option A Answer: Option B . .
10. What is meant by parallel-loading the register? 7. When the output of a tri-state shift register is disabled, the output level is placed in a: A.
float state
B.
LOW state
C.
high impedance state
D.
float state and a high impedance state
Answer: Option D
A.
a ring counter has fewer flip-flops but requires more decoding circuitry
B.
a ring counter has an inverted feedback path
C.
a johnson counter has more flip-flops but less decoding circuitry
D.
a johnson counter has an inverted feedback path
Answer: Option D
A.
shift register sequencer
B.
clock
C.
johnson
D.
binary
B.
Loading data in two of the flip-flops
C.
Loading data in all four flip-flops at the same time
D.
Momentarily disabling the synchronous SET and RESET inputs
A.
tri-state
B.
end around
C.
bidirectional universal
D.
conversion
Answer: Option C
.
12. What happens to the parallel output word in an asynchronous binary down counter whenever a clock pulse occurs?
.
9. A sequence of equally spaced timing pulses may be easily generated by which type of counter circuit?
Shifting the data in all flip-flops simultaneously
Answer: Option C 11. What is a shift register that will accept a parallel input and can shift data left or right called?
.
8. A comparison between ring and johnson counters indicates that:
A.
A.
The output word decreases by 1.
B.
The output word decreases by 2.
C.
The output word increases by 1.
D.
The output word increases by 2.
Answer: Option A
.
13. Mod-6 and mod-12 counters are most commonly used in:
A.
frequency counters
B.
multiplexed displays
C.
digital clocks
D.
power consumption meters
.
4. The two's complement system is to be used to add the signed numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.
Answer: Option C
XXXVIII - ARITHMETIC OPERATIONS AND CIRCUITS
1. When 1100010 is divided by 0101, what will be the decimal remainder? A.
2
B.
3
C.
4
D.
6
A.
–14 and –13; –27
B.
–113 and –114; 227
C.
–27 and –13; 40
D.
–11 and –16; –27
Answer: Option A
Answer: Option B .
.
5. The fast carry or look-ahead carry circuits found in most 4-bit parallel-adder circuits: 2. What are the two types of basic adder circuits?
A.
increase ripple delay
A.
half adder and full adder
B.
add a 1 to complemented inputs
B.
half adder and parallel adder
C.
reduce propagation delay
C.
asynchronous and synchronous
D.
determine sign and magnitude
D.
one's complement and two's complement
Answer: Option A
Answer: Option C 6. How many basic binary subtraction operations are possible? A.
4
B.
3
C.
2
D.
1
. Answer: Option D
3. Adding the two's complement of –11 + (–2) will yield which two's complement answer? A.
1110 1101
B.
1111 1001
C.
1111 0011
D.
1110 1001
Answer: Option C
.
7. How many basic binary subtraction combinations are possible? A.
4
B.
3
C.
2
D.
1
Answer: Option A Answer: Option D . .
8. Use the two's complement system to add the signed numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.
12. When multiplying in binary the decimal values 13 × 11, what is the third partial product?
A.
–14 and –13; –27
A.
100000
B.
100001
B.
–113 and –114; 227
C.
0000
D.
1011
C.
–27 and –13; 40
D.
–11 and –16; –27
Answer: Option A
Answer: Option A
.
. 13. The range of an 8-bit two's complement word is from:
9. The selector inputs to an arithmetic-logic unit (ALU) determine the: A.
selection of the IC
B.
arithmetic or logic function
C.
data word selection
D.
clock frequency to be used
A.
+12810 to –12810
B.
–12810 to +12710
C.
+12810 to –12710
D.
+12710 to –12710
Answer: Option B
XXXIX - SEMICONDUCTOR MEMORY Answer: Option B 1. A computerized self-diagnostic for a ROM test uses: .
A.
the check-sum method
B.
a ROM listing
C.
ROM comparisons
D.
a checkerboard test
10. Adding in binary, the decimal values 26 + 27 will produce a sum of: A.
111010
B.
110110
C.
110101
D.
101011
Answer: Option A
. Answer: Option C 11. Binary subtraction of a decimal 15 from 43 will utilize which two's complement? A.
101011
B.
110000
C.
011100
D.
110001
2. How many storage locations are available when a memory device has twelve address lines?
A.
144
B.
512
C.
2048
D.
4096
6. Select the best of read-only memory (ROM). A.
nonvolatile, used to store information that changes during system operation
B.
nonvolatile, used to store information that does not change during system operation
C.
volatile, used to store information that changes during system operation
D.
volatile, used to store information that does not change during system operation
Answer: Option D
.
Answer: Option B 3. Which of the following memories uses a MOSFET and a capacitor as its memory cell? A.
SRAM
B.
DRAM
C.
ROM
D.
DROM
Answer: Option B
.
7. Advantage(s) of an EEPROM over an EPROM is (are):
.
4. Which of the following best describes nonvolatile memory? A.
memory that retains stored information when electrical power is removed
B.
memory that loses stored information when electrical power is removed
C.
magnetic memory
D.
nonmagnetic memory
A.
the EPROM can be erased with ultraviolet light in much less time than an EEPROM
B.
the EEPROM can be erased and reprogrammed without removal from the circuit
C.
the EEPROM has the ability to erase and reprogram individual words
D.
the EEPROM can erase and reprogram individual words without removal from the circuit
Answer: Option D
.
Answer: Option A 8. Which of the following RAM timing parameters determine(s) its operating speed? .
A.
tacc
B.
taa and tacs
C.
t1 and t3
D.
trc and twc
5. The access time (tacc) of a memory IC is governed by the IC's: A.
internal address buffer
B.
internal address decoder
C.
volatility
D.
internal address decoder and volatility
Answer: Option B
Answer: Option C
.
9. Memory that loses its contents when power is lost is: A.
nonvolatile
B.
volatile
C.
random
D.
static
.
Answer: Option B 13. What is the principal advantage of using address multiplexing with DRAM memory? .
10. Select the best of the fusible-link PROM. A.
user programmable, one-time programmable
B.
manufacturer programmable, one-time programmable
C.
user programmable, reprogrammable
D.
manufacturer programmable, reprogrammable
Answer: Option A 11. A nonvolatile type of memory that can be programmed and erased in sectors, rather than one byte at a time is: A.
flash memory
B.
EPROM
C.
EEPROM
D.
MPROM
A.
reduced memory access time
B.
reduced requirement for constant refreshing of the memory contents
C.
reduced pin count and decrease in package size
D.
no requirement for a chip-select input line, thereby reducing the pin count
Answer: Option C
XXXX - ANALOG AND DIGITAL CONVERTERS
1. Which of the following is a type of error associated with digital-to-analog converters (DACs)? A.
nonmonotonic error
B.
incorrect output codes
C.
offset error
D.
nonmonotonic and offset error
Answer: Option D
Answer: Option A .
.
2. A 4-bit R/2R digital-to-analog (DAC) converter has a reference of 5 volts. What is the analog output for the input code 0101. 12. Which of the following best describes static memory devices? A.
memory devices that are magnetic in nature and do not require constant refreshing
B.
semiconductor memory devices in which stored data is retained as long as power is applied
C.
memory devices that are magnetic in nature and require constant refreshing
D.
semiconductor memory devices in which stored data will not be retained with the power applied unless constantly refreshed
0.3125 V
B.
3.125 V
C.
0.78125 V
D.
–3.125 V
Answer: Option B
. Answer: Option B
A.
3. A binary-weighted digital-to-analog converter has an input resistor of 100 k . If the resistor is connected to a 5 V source, the current through the resistor is: A.
50
B.
5 mA
C.
500
D.
50 mA
Answer: Option C
A . A
7. The primary disadvantage of the flash analog-to digital converter (ADC) is that: Answer: Option A
A.
it requires the input voltage to be applied to the inputs simultaneously
B.
a long conversion time is required
C.
a large number of output lines is required to simultaneously decode the input voltage
D.
a large number of comparators is required to represent a reasonable sized binary number
.
4. What is the resolution of a digital-to-analog converter (DAC)? A.
It is the comparison between the actual output of the converter and its expected output.
B.
It is the deviation between the ideal straight-line output and the actual output of the converter.
C.
It is the smallest analog output change that can occur as a result of an increment in the digital input.
D.
It is its ability to resolve between forward and reverse steps when sequenced over its entire range.
Answer: Option D
.
8. A binary-weighted digital-to-analog converter has a feedback resistor, Rf, of 12 k . If 50 A of current is through the resistor, the voltage out of the circuit is:
Answer: Option C
.
A.
0.6 V
B.
–0.6 V
C.
0.1 V
D.
–0.1 V
Answer: Option B 5. The practical use of binary-weighted digital-to-analog converters is limited to: A.
R/2R ladder D/A converters
B.
4-bit D/A converters
C.
8-bit D/A converters
D.
op-amp comparators
.
9. What is the major advantage of the R/2R ladder digitalto-analog (DAC), as compared to a binary-weighted digital-to-analog DAC converter?
Answer: Option B 6. The difference between analog voltage represented by two adjacent digital codes, or the analog step size, is the: A.
quantization
B.
accuracy
C.
resolution
D.
monotonicity
A.
It only uses two different resistor values.
B.
It has fewer parts for the same number of inputs.
C.
Its operation is much easier to analyze.
D.
The virtual ground is eliminated and the circuit is therefore easier to understand and troubleshoot.
B.
stabilize the comparator's threshold voltage during the conversion process
C.
stabilize the input analog signal during the conversion process
D.
sample and hold the D/A converter staircase waveform during the conversion process
Answer: Option A
.
Answer: Option C 10. The resolution of a 0–5 V 6-bit digital-to-analog converter (DAC) is: A.
63%
B.
64%
C.
1.56%
D.
15.6%
XXXXI - COMPUTER HARDWARE AND SOFTWARE
1. When referring to instruction words, a mnemonic is:
Answer: Option C 11. In a flash analog-to-digital converter, the output of each comparator is connected to an input of a: A.
decoder
B.
priority encoder
C.
multiplexer
D.
demultiplexer
Answer: Option B
A.
a short abbreviation for the operand address
B.
a short abbreviation for the operation to be performed
C.
a short abbreviation for the data word stored at the operand address
D.
shorthand for machine language
Answer: Option B
.
. 2. What is the difference between mnemonic codes and machine codes?
12. Which is not an analog-to-digital (ADC) conversion error? A.
differential nonlinearity
B.
missing code
C.
incorrect code
D.
offset
A.
There is no difference.
B.
Machine codes are in binary, mnemonic codes are in shorthand English.
C.
Machine codes are in shorthand English, mnemonic codes are in binary.
D.
Machine codes are in shorthand English, mnemonic codes are a high-level language.
Answer: Option B Answer: Option A
. .
3. Which bus is bidirectional? 13. Sample-and-hold circuits in analog-to digital converters (ADCs) are designed to: A.
sample and hold the output of the binary counter during the conversion process
A.
data bus
B.
control bus
C.
address bus
D.
multiplexed bus
D.
address bus
Answer: Option A
Answer: Option B
.
.
4. The software used to drive microprocessor-based systems is called:
8. The technique of assigning a memory address to each I/O device in the SAM system is called:
A.
assembly language programs
A.
wired I/O
B.
firmware
B.
I/O mapping
C.
BASIC interpreter instructions
C.
dedicated I/O
D.
flowchart instructions
D.
memory-mapped I/O
Answer: Option A
Answer: Option D
.
.
5. A microprocessor unit, a memory unit, and an input/output unit form a: A.
CPU
B.
compiler
C.
microcomputer
D.
ALU
Answer: Option C 6. How many buses are connected as part of the 8085 microprocessor? A.
2
B.
3
C.
5
D.
8
Answer: Option B
.
9. How many bits are used in the data bus? A.
7
B.
8
C.
9
D.
16
Answer: Option B
.
10. A port can be: A.
strictly for input
B.
strictly for output
C.
bidirectional
D.
all the above
7. Which of the following is not a computer bus? A.
data bus
B.
timer bus
C.
control bus
Answer: Option C 11. Which of the following is not a basic element within the microprocessor? A.
microcontroller
B.
arithmetic-logic unit (ALU)
C.
temporary register
D.
accumulator
Answer: Option A
.
12. How many bits are used in the address bus? A.
7
B.
8
C.
9
D.
16
Answer: Option D
.
13. Exceptions to the 8085 microprocessor normal operation are called: A.
jump instructions
B.
decoding
C.
interrupts
D.
jump instructions or interrupts
Answer: Option D
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