Past Board Exam Problem.........

CHAPTER 2 DIODE APPLICATIONS CHAPTER 2 DIODE APPLICATIONS 1. An open primary or secondary winding of a power supply transformer results in 0V 2. The output frequency of a half-wave rectifier is _________to/of the input frequency Equal 3. What is the average value of the half-wave rectified voltage given 25 V as its peak amplitude? 7.95 V 4. The PIV rating of the bridge diodes is __________to/than that required for the centertapped configuration. Less 5. Diode circuits used to clip off portions of signal voltages above or below certain levels, Clippers 6. The output frequency of a full-wave rectifier is ________ the input frequency Twice 7. A transformer is generally specified based on _____________rather than the turns ratio, Secondary voltage 8. The period of a full-wave rectified voltage is ____________ that of a half-wave rectified voltage Half 9. The indication of the effectiveness of the filter is called Ripple factor 10. Eliminates the fluctuations in the rectified voltage and produces a relatively smooth dc voltage Filter

14. Maximum voltage appearing across the diode in reverse bias PIV 15. Caused by the charging and discharging of the filter capacitor Ripple voltage 16. A systematic process of isolating, identifying, and correcting a fault in a circuit or system Troubleshooting 17. Allows unidirectional current through the load during the entire 360° of the input cycle Full-wave rectifier 18. Allows current through the load only during onehalf of the cycle. Half-wave rectifier 19. Generally used because of the surge current that initially occur s when power is first turned on Slow-blow type fuse 20. A figure of merit used to specify the performance of a voltage regulator regulation CHAPTER 3 SPECIAL- PURPOSE DIODES CHAPTER 3 SPECIAL- PURPOSE DIODES 1. Diodes that were designed to operate in reverse breakdown Zener diode 2. A device that operates in reverse bias photodiode

11. Circuit that maintains a constant dc voltage for variations in the input line voltage or in the load Regulator

3. A zener diode operating in breakdown acts as a Voltage regulator 4. A positive temperature means that the zener voltage Increases with an increase in temperature on decreases with decrease in temperature.

12. A type of full-wave rectifier that uses two diodes connected to the secondary of a center-tapped transformer Center-tapped rectifier

5. A diode that always operates in reverse-bias and is doped to maximize the inherent capacitance of the depletion region is Laser

13. Use clamping action to increase peak rectified voltages without the necessity of increasing the transformer’s voltage rating Voltage multipliers

6. When the light-emitting diode (LED) is forwardbiased, __________pass the pn junction and recombine with____________ in the _________material.

Electrons, holes, p-type 7. The first visible red LEDs were produced using GaAsp 8. The normalized output of the visible red, yellow, green and blue LED peaks at __________________ (nm) respectively. 660,590,540, and 460 9. Organic LEDs and LEDs produce light through the process of __________ and ___________ respectively. Electrophophorescence and electroluminescence 10. An increase in the amount of light intensity produces an increase in Reverse current 11. A diode that can be used as a variable-resistance device controlled by light intensity. Photodiode 12. A diode that operates only with majority carriers Schottky diode 13. A diode that takes advantage of the variable forward resistance characteristic. PIN diode 14. No reverse leakage current Schottky diode 15. Diode used in VHF and fast switching applications Step- Recovery diode 16. When a PIN diode is forward-biased, it acts like a Current-controlled variable resistance 17. If a tunnel diode is placed in series with the tank circuit and biased at the center of the negativeresistance portion of its characteristic curve, a _________ will result in the output. Constant sinusoidal voltage 18. The tunnel diode is only used at VHF

CHAPTER 4 BIPOLAR JUNCTION TRANSISTORS CHAPTER 4 BIPOLAR JUNCTION TRANSISTORS 1. Which is the least of the three transistor currents? Base 2. The ratio of the dc collector current to the dc base current of the transistor is, dc beta/dc current gain 3. the ratio of the dc collector current to the dc emitter current dc alpha 4. Determine the base current given dc beta=100 , dc alpha=0.85, and IC= 3.70mA 0.037mA 5. Nonconducting state of a transistor Cutoff 6. State of a BJT in which the collector current has reached maximum and is dependent of the base current Saturation 7. Neither the base-emitter nor the base-collector junctions are forward-biased cutoff 8. dc beta varies with collector current and temperature 9. hFE varies with which transistor current/s? Collector only 10. Converts light energy to electrical signal Phototransistor 11. Devices used to electrically isolate circuits Optocouplers 12. A key parameter in optocouplers is the CTR. CTR standsfor Current transfer ratio 13. Indication of how efficiently a signal is coupled from input to output CTR

19. In a varactor diode, what happens to the capacitance if the reverse-bias voltage decreases a. Increases

14. RF transistors are designed to operate at EHF

20. The varactor capacitance ratio is also known as a. Tuning ratio

15. What transistor category/ies uses plastic or metal packages?

General-purpose transistors 16. To operate as an amplifier, BE junction must be forward-biased and the BC junction must be reversebiased. This is called Forward-reverse bias

10. If an amplifier is not biased with correct dc voltages on the input and output, it can go ___________ when an input signal is applied. Saturation or cutoff

17. In a phototransistor, what transistor current/s is produced and controlled by light? Base

11. Given a voltage-divider biased BJT, determine IC given VCC, R1, R2, RC, and RE which are 10V, 10kohms, 4.7kohms, 1kohm, and 470ohms respectively. Use βDC= 100. 5.31mA

18. Two basic package types Through-hole and surface mount

12. What is the value of VCE in no.20? 2.19 V

19. The process of increasing the power, voltage, or current by electronic means. Amplification

13. If an emitter resistor is added to a base bias circuit, what is the value of the emitter current given VCC, RE, RC, and RB as 10V, 1kΩ, 470Ω, and 180kΩ, respectively. Use βDC=100. 3.32mA

CHAPTER 5 TRANSISTOR BIAS CIRCUITS 1. What biasing method is common in switching circuits? Base bias 2. A Base bias in linear region shows that it is Directly dependent on dc beta 3. In an emitter-feedback bias, if the collector currentincreases, the emitter voltage Increases 4. What happens to the base voltage in no. 10? Increases 5. In an emitter-feedback, the increase in base voltage _________ the base current. Reduces 6. For collector-feedback bias, what provides the bias for the base-emitter junction? Collector voltage 7. As temperature goes up in a collector-feedback circuit, βDC and VBE goes _______ and __________, respectively. Up and down 8. Collector-feedback bias provides good stability using negative feedback from Collector to base 9. Innovations in technology would allow a doubling of the number of transistors in a given space every year and that the speed of those transistors would increase. This prediction is widely known as Moore’s law

14. Calculate for VCE in no. 22 5.12 V 15. If the dc beta in the preceding drops half of its originalvalue, find the percent change in IC. 39.16% 16. What is the percent change in VCE? 27.17% 17. The region along the load line including all points between saturation and cutoff Linear region 18. A voltage divider for which loading effects can be neglected Stiff voltage divider 19. The base bias circuit arrangement has poor stability because its Q-point varies widely with Dc beta 20. The purpose of biasing a circuit is to establish a proper stable ________. Q-point 21. The process of returning a portion of a circuit’s output back to the input in such a way as to oppose or aid a change in the output Feedback

CHAPTER 6 BJT AMPLIFIERS CHAPTER 6 BJT AMPLIFIERS 1. Amplifiers designed to handle small __________ signals are referred to as small-signal amplifiers. ac only 2. Which of the r parameters is the most important? r’e 3. Determine the ac emitter resistance that is operating with a dc emitter current of 5mA. 5.0 Ω 4. If βac=hfe, αac=? hfb 5. Which of the three amplifier configurations exhibit high voltage gain and high current gain? Common-emitter 6. An amplifier configuration which has a voltage gain of approximately 1, a high input resistance and current gain, Common-collector 7. An amplifier configuration which provides high voltage gain with a maximum current gain of 1. Common-base 8. Which of the amplifier configurations is the most appropriate for certain applications where sources tend to have low-resistance outputs? Common-base 9. In a common-emitter amplifier, any change in input signal voltage results in Opposite change in collector signal voltage 10. The ac voltage gain is the ratio of ac output voltage at the collector to ac input voltage at the base 11. the reduction in signal voltage as it passes through a circuit attenuation

It decreases the ac voltage gain 14. The measure of how well an amplifier maintains its design values over changes in temperature, Stability 15. Swamping is a method used to minimize the effect of the ____________without reducing the voltage gain to its minimum value. ac emitter resistance 16. ___________ contains two transistors. The collectors of two transistors are connected and the emitter of the first drives the base of the second. Darlington pair 17. _____________ consists of two types of transistors, npn and a pnp. Complementary Darlington 18. An amplifier configuration in which the input signal is capacitively coupled to the emitter and the output is capacitively coupled from the collector, Common-base 19. Which of the amplifier configurations is/are useful at high frequencies when impedance matching is required? Common-base 20. The power gain of a common-base amplifier is approximately equal to Voltage gain 21. BJT amplifier that produces output that are a function of the difference between two input voltages, Differential amplifier 22. Ideally, a diff-amp provides a very high gain for single-ended or differential signals and _____________ gain for common-mode signals. 0 23. Input signals are out of phase Differential amplifier

12. the overall voltage gain of the common-emitter amplifier is the product of the voltage gain from base to collector and reciprocal of the attenuation

CHAPTER 7 POWER AMPLIFIERS CHAPTER 7 POWER AMPLIFIERS

13. Without the bypass capacitor, the CE amplifier’s emitter is no longer at ac ground. How does this affect the amplifier?

1. It is the product of Q-point current and voltage of a transistor with no signal input Power dissipation

Cutoff 2. The ____________ of an amplifier is the ratio of the output signal power supplied to a load to the total power from the dc supply. Efficiency 3. Which amplifier operates in the linear region for 180 deg. Of the input cycle when biased in cutoff and is in cutoff for 180 deg? Class B

16. Operates in the linear region where the output signal is an amplified replica of the input signal Class A 17. Amplifiers that have the objective of delivering power to a load Power amplifers

4. These amplifiers are biased to conduct for slightly more than 180 deg. Class AB

18. When the Q-point is at the center of the ac load line, a maximum class ________ signal can be obtained. A

5. An amplifier that is generally used in Radio Frequencyapplications Class C

19. The maximum efficiency of capacitively coupled class A amplifier cannot be higher than 25%

6. Implemented with a laser diode Current mirror

20. The low efficiency of class A amplifiers limits their usefulness to small power applications that require usually less than ________. 1W

7. An amplifier that is biased below cutoff and is normally operated with resonant circuit load Class C 8. The four classes of power amplifiers are classified based on the percentage of the ____________which the amplifier operates in its ________region Input cycle, linear 9. It is the ratio of the output power to the input power Power gain 10. Product of the rms load current and the rms load voltage Output power 11. A type of class B amplifier with two transistors in which one transistor conducts for one half-cycle and the other conducts for the other half-cycle Push-pull 12. Amplifiers that are generally used in Radio Frequency Applications. Class C amplifiers 13. Another term for complementary Darlington Sziklai pair 14. An advantage of push-pull class B and class AB amplifiers over class A Efficiency 15. The Q-point is at _________ at class B operation

CHAPTER 8 FIELD –EFFECT TRANSISTORS CHAPTER 8 FIELD –EFFECT TRANSISTORS 1. FETs are preferred device in low-voltage switchingapplications; while______ transistor is generally used in high-voltage switching applications. IGBT 2. What type of JFET operates with a reverse-biased pn junction to control current in the channel? JFET 3. An n-channel universal transfer characteristic curve is also known as Transconductance curve 4. The change in drain current for a given change in gate-to-source voltage with the drain-to-source voltage constant Forward transconductance 5. What is the most common type of JFET bias? Self-bias 6. It is a method for increasing the Q-point stability of a self-biased JFET by making the drain current essentially independent of gate-to-source voltage Current-source bias 7. What JFET bias uses a BJT as a constant-current source?

Current-source bias

IGBT

8. For increased Q-point stability, the value of RS in the self-bias circuit is increased and connected to a negative supply voltage. This sometimes called Dual-supply bias

21. Has a lateral channel structure and is a type of enhancement MOSFET designed for power applications. LDMOSFET

9. VGS varies quite a bit for JFET self-bias and voltage-divider bias but ID is much more stable with Voltage-divider bias 10. ____________ is sometimes called depletion/enhancementMOSFET. D-MOSFET 11. LDMOSFET has a lateral channel structure and is a type of Enhancement MOSFET 12. It is an example of the conventional EMOSFET designed to achieve higher power capability VMOSFET 13. Following are the three ways to bias a MOSFET except Current-source bias 14. The insulated-gate bipolar transistor combines which two transistors that make it useful in highvoltage and high-current switching applications? BJT and MOSFET 15. What are the three terminals of IGBT? Gate, collector, emitter 16. In terms of switching speed, __________ switch fastest and _____________ switch slowest. MOSFETs, BJTs 17. In a MOSFET, the process of removing or depleting the channel of charge carriers and thus decreasing the channel conductivity Depletion 18. The ratio of change in drain current to a change in gate-to source voltage in a FET Transconductance 19. A FET is called a ______________ because of the relationship of the drain current to the square of a term containing gate-to-source voltage Square-law device 20. Combines features from both the MOSFET and the BJT that make it useful in high-voltage and highcurrent switching applications.

CHAPTER 9 FET AMPLIFIERS AND SWITCHING CIRCUITS CHAPTER 9 FET AMPLIFIERS AND SWITCHING CIRCUITS 1. An amplifier that primarily uses only MOSFETs. Class D 2. A process in which an input signal is converted to a series of pulses with widths that varies proportionally to the amplitude of the input signal. PWM 3. It removes the modulating frequency and harmonics and passes only the original signal to the output. Low-Pass Filter 4. The voltage gain of a common-drain amplifier is always Slightly less than 1 5. The load resistance connected to the drain of a common-source amplifier reduces ____________ Voltage gain 6. What is the relationship between the input resistance of a common-gate amplifier to its transconductance? They are inversely proportional 7. The efficiency of a class D amplifier approaches 100% 8. The input signal is applied to the gate and the output is taken from source Common-drain 9. A nonlinear amplifier in which the transistors are operated as switches Class D 10. A device that switches an analog signal on and off Analog switch 11. Consists of two or more analog switches that

connect sample portions of their analog input signals to single output in a time sequence Analog multiplexer

product of the voltage gain and the bandwidth is always constant when the roll-off is -20 dB/ decade. Gain-bandwidth product

12. Used in low-power digital switching circuits CMOS

7. Critical frequencies are values of frequency at which the RCcircuits reduce the voltage gain to ____________ of its midrange value. 70.7%

13. Amplifier commonly used as frequency multiplier Class C 14. The least efficient amplifier Class A 15. An amplifier that is biased below cutoff Class c 16. A class of amplifier that operates in the linear region for only a small part of the input cycle Class C 17. In a class AB amplifier, if the VBE drops are not matched to the diode drops or if the diodes are not in thermal equilibrium with the transistors, this can result in Thermal runaway

CHAPTER 10 AMPLIFIER FREQUENCY RESPONSE CHAPTER 10 AMPLIFIER FREQUENCY RESPONSE 1. The frequency at which the output power drops to one-half of its midrange value Corner frequency 2. At the critical frequencies the output voltage is 70.7% of its midrange value. What is the value of voltage gain in dB? -3 dB 3. What is the other term for lower critical frequency? All of the above 4. The condition where the gain is down 3 dB is logically called _________ of the amplifier response -3 dB point 5. The upper and lower dominant critical frequencies are sometimes called Half-power frequencies 6. A characteristic of an amplifier in which the

8. An octave of frequency change is a ________ -times change 2 9. Which of the following has no effect on the lowfrequency response? Internal transistor capacitances 10. What is the gain that occurs for the range of frequencies between the lower and upper critical frequencies? Midrange gain 11. Which of the following is not a method in frequency response measurement? Roll-off measurement 12. If the voltage gain is less than one, what is the value of the dB gain? Negative 13. A plot of dB voltage gain versus frequency on semilog graph paper Bode plot 14. The critical frequency at which the curve “breaks” into a -20dB/decade drop Lower break frequency 15. The change in gain or phase shift over a specified range of input signal frequencies Frequency response 16. A unit of logarithmic gain measurement and is commonly used to express amplifier response Decibel 17. The lower and upper critical frequencies of an amplifier can be determined using the _____________ method by applying a voltage step to the input of the amplifier and measuring the rise and fall times of the resulting output voltage Step-response method 18. The coupling an bypass capacitors of an amplifier affect the _________ frequency response: high or low Low

19. The internal transistor capacitances affect the _________ frequency response: high or low High 20. Two frequency response measurement Frequency/amplitude and step 21. The Miller input and output capacitances for a BJT inverting amplifier depends on Voltage gain

9. The value of gate current necessary to switch the SCR from the forward-blocking region to the forward-conduction region under specified conditions. Gate Trigger Current 10. A four-layer semiconductor device that operates essentially as does the conventional SCR except that it can also be light-triggered. LASCR

22. When dB is negative, it is usually called_______ Attenuation

11. Functions basically like two parallel 4- layer diodes turned in opposite directions. Diac

CHAPTER 11 THYRISTORS CHAPTER 11 THYRISTORS

12. A diac with gate terminal Triac

1. It is like the four-layer diode but with the added gate connection SCR 2. This is the maximum continuous anode current that the device can withstand in the conduction state under specifies conditions. Average forward current 3. What bilateral thyristor functions basically like two parallel SCRs turned in opposite directions with a common gate terminal? Triac 4. ____________ does not belong to the thyristor family because it does not have a four-layer type of construction. UJT 5. It can be used a trigger device for SCRs and triacs. UJT 6. It is a type of three-terminal thyristor that is triggered into conduction when the voltage at the anode exceeds the voltage at the gate. PUT

13. A four-terminal thyristor that has two gate terminals that are used t trigger the device on and off Silicon Controlled Device (SCS) 14. A type of three-terminal thyristor that is triggered into conduction when the voltage at the anode exceeds the voltage at the gate. Programmable Unijunction Transistor (PUT) 15. The characteristic of a UJT that determines its turn-on point Standoff-ratio 16. The four-layer diode is also called Shockley diode 17. The region that corresponds to the on condition of the SCR where there is forward current from anode to cathode through the very low resistance of the SCR Forward_ conduction region 18. The SCR can only be turned on using its _________ terminal Gate 19. Acts as the trigger source in the LASCRs Light

7. A region of forward bias in which the device has a very high forward resistance and is in the off state Forward-blocking region

20. A thyristor that conducts when the voltage across its terminals exceeds the breakover potential 4-layer diode

8. A method for turning-off the SCR that basically requires momentarily forcing current through the SCR in the direction opposite to the forward conduction Forced commutation

21. Basic methods of for turning off an SCR Anode current interruption and forced commutation

CHAPTER 12 THE OPERATIONAL AMPLIFIER CHAPTER 12 THE OPERATIONAL AMPLIFIER 1. The measure of an amplifier’s ability to reject common-mode signals CMRR 2. It is the typical value of input offset voltage in the ideal case. 0V 3. It is the dc current required by the inputs of the amplifier to properly operate the first stage. Input bias current 4. It is the resistance viewed from the output terminal of the op-amp Output impedance 5. The total resistance between the inverting and noninverting inputs Differential input impedance

varying function relative to a reference. Phase shift 14. The three terminals of the basic op-amp not including power and ground Inverting input, noninverting input, and output 15. It has the highest input impedance and the lowest output impedance of the three amplifier configurations Voltage-follower 16. The _________ of an op-amp equals the upper critical frequency. Bandwidth 17. Two types of op-amp input operation. Differential mode and common-mode 18. A ____________ differentiator uses a capacitor in series with the inverting input. Ideal 19. An ideal op-amp has ___________ value for voltage gain, bandwidth, and input impedance. Infinite

6. Differential impedance is measured by determining the change in ___________ for a given change in differential input voltage. Bias current

20. What should be the output voltage of an op-amp when the differential input is zero Zero

7. Common temperature coefficient for the offset current 0.5nA/°C

21. The ideal op-amp has __________ output impedance Zero

8. Functions of negative feedback in an op-amp Stabilize gain and increase frequency response

22. The three basic op-amp configurations Inverting, noninverting, and voltage follower

9. The voltage gain of an op-amp with external feedback Closed-loop voltage gain

23. The closed-loop voltage gain is _________ than the open-loop voltage gain. (more or less) Less

10. A special case of the noninverting amplifier where all of the output voltage is fed back to the inverting input by a straight connection Voltage-follower configuration

24. Does the gain of an op-amp decreases or increases as frequency increases above the critical frequency Decreases

11. The value of the frequency at which the gain steadily decreases to a point where it is equal to unity Unity-gain frequency Or unity gain bandwidth

25. Devices such as the diode and the transistor which are separate devices that are individually packaged and interconnected in a circuit with other devices to form a complete, functional unit. Discrete components

12. It is always equal to the frequency at which the op-amp’s open- loop gain is unity or 0 dB. Gain-bandwidth product 13. The relative angular displacement of a time-

26. Most op-amps operate with how many dc supply voltage? 2 (positive and negative)

27. Datasheets often refer to the open-loop voltage gain as the ______________ Large-signal voltage gain

CHAPTER 13 BASIC OP-AMP CIRCUITS CHAPTER 13 BASIC OP-AMP CIRCUITS 1. A common interfacing process often used when a linearanalog system must provide inputs to a digital system. A/D conversion 2. Method of A/D conversion that uses parallel comparators to compare the linear input signal with various reference voltages developed by a voltage divider Flash 3. Produces an output that is proportional to the rate of change of the input voltage Differentiator 4. The difference between the UTP and the LTP Hysteresis voltage 5. Used to generate pulse waveform from the sine wave output of the audio generator. Voltage comparator 6. When the output is at the maximum positive voltage and the input exceeds UTP, the output switches to the _________ negative voltage Maximum 7. Uses a capacitor in the feedback path which is open to dc. This implies that the gain at dc is the open-loop gain of the op-amp. Practical integrator 8. Gives an op-amp noise immunity Hysteresis 9. Used to detect positive and negative voltages by connecting a fixed reference voltage source to the inverting input of a zero-level detector. Nonzero-Level detection

12. The output of Schmitt trigger is Pulse waveform 13. In a comparator with output bounding, what type of diode is used in the feedback loop? Zener 14. Necessary components for the design of a bounded comparator Rectifier and zener diodes 15. Type of circuit that uses comparators Nonzero-level detector 16. Variations of the basic summing amplifier Averaging and scaling amplifier 17. Differentiation of a ramp input produces a step output with an amplitude proportional to the _________ Slope 18. Another term for flash Simultaneous 19. Integration of a step input produces a ramp output with the slope proportional to the _________ Amplitude CHAPTER 14 SPECIAL PURPOSE OPAMP CIRCUITS CHAPTER 14 SPECIAL PURPOSE OP-AMP CIRCUITS 1. Provides dc isolation between input and output Isolation amplifier 2. Ratio of the output current to the input voltage Transconductance 3. Transconductance is __________ of an OTA Gain 4. A comparator with hysteresis where the input voltage is large enough to drive the device into its saturated states Schmitt trigger

10. A good example of hysteresis Thermostat

5. The ______________ of a number is the power to which the base must be raised to get that number. Logarithm

11. A comparator with three trigger points Schmitt Trigger

6. An amplifier that produces an output that is proportional to the logarithm of the input.

Log amplifier 7. Used in applications where it is necessary to have an output current that is controlled by an input voltage. Voltage-to-current converter 8. The circuit used to detect the peak of the input voltage and store that peak voltage on a capacitor. Peak detector 9. The exponent to which the base e must be raised in order to equal a given quantity. Natural logarithm 10. In an OTA, transconductance varies with _________. Bias current 11. Amplifiers that are often used in HF communication systems, including fiber optics, for processing wide dynamic range signals. Log and antilog amplifiers 12. The key characterisctic of an instrumentation amplifier CMRR 13. The voltage gain of instrumentation amplifier is set by a Resistor 14. The log amplifier may use the ___________ junction of a BJT in the feedback loop Base-emitter 15. The main purpose of an instrumentation amplifier is to amplify _____ signals that are riding on _____ common-mode voltages. small, large 16. The ___________ of an OTA is the input voltage times the transconductance Output current 17. The operation of log and antilog amplifiers is based on the __________ characteristics of a pn junction Nonlinear (logarithmic) 18. A log amplifier has a pn junction in the feedback loop, and an antilog amplifier has a pn junction in __________ with the input Series

19. In a peak detector, an op-amp is used as a __________ to charge a capacitor through a diode to the peak value of the input voltage. Comparator 20. A basic instrumentation amplifier is formed by three op-amps and ________ resistors, including the gain setting resistor. Seven (7) 21. An oscillator that can be either amplitude or pulse modulated by the signal from the input amplifier High-frequency oscillator