ELEX Reviewer 1

CHAPTER1 Hans Oersted

Relationship of magnetism and electricity that served as the foundation of theory for electromagnets Most important electrical effect is the magnetic effect

Michael Faraday

Theory of electromagnetic induction Current Carrying conductor would move when placed in a magnetic field

James Maxwell

Electromagnetic Theory of light

Andre Ampere

Demonstrated that there are magnetic effects around every current carrying conductor and that these conductors act like a magnet

Kamerlingh Onnes

Superconductivity

Faraday’s Law

Whenever a conductor cuts a magnetic flux, an emf is induced in it

Faraday’s 1st Law

The magnitude of induced emf is directly proportional to the rate of change of flux linkages

Faraday’s 2nd Law

Whenever the flux linking a coil or current changes, an emf is induced in it

Coulumb’s 1st Law

Force between 2 magnetic poles is directly proportional to their strengths

Coulumb’s 2nd Law

Force between 2 magnetic poles id inversely proportional to the distance between them

Child’s Law

Current in a thermionic diode varies directly with the three halves power of anode voltage and inversely with the square of distance between the electrodes

Wiedmann-Franz Law

Ratio of the thermal conductivity to the electric conductivity is directly proportional to the absolute temp for all metals

Curie’s Law

The magnetic susceptibilities of most paramagnetic materials are inversely proportional to their absolute temperatures

Curie-Weiss Law

Law relating the M and E susceptibilities and the absolute temperature

Ewing’s theory of Ferromagnetism

Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied fields and magnets

Ampere’s Theorem

States that a current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength is equal to the strength of current

Right hand rule

Also called corkscrew rule

End Rule

If looking at any one end of a solenoid, the direction of current is found to be clockwise then the end under observation is a south pole

Helix Rule

If a solenoid is held by the right hand with the fingers pointing to the direction of the current flow, the outstretched thumb will point to the north pole

Unit Pole

A pole which when placed in air from a similar and equal pole repels it with a force of 1/4pi newtons

Magnetic Pole

Point in a magnet where the intensity of the magnetic lines of force is max

Magnetic Axis

Straight Line passing through 2 poles of a magnet

Dia

UrUo ; aluminum, platinum, manganese, chromium, oxygen

Greatest % of materials Ferro

Ur>>1 U>>Uo ; cobalt

10^-10 m

Diameter of atom

10^-15 to 10^-16 m

Diameter of atomic nucleus

1.1 x 10^-8 cm

Diameter of Hydrogen Atom

Permeance

Reciprocal of Reluctance / Analogous to conductance

Coercivity

Amount of magnetizing force to counter balance the residual magnetism

Leakage Factor

Ratio of flux in iron to flux in air (iba iba yung tawag sa book at sa coaching)

Intensity Magnetism

The flux density produced in it due to its own magnetism

Hysteresis

Lag between B and H

Ferrites

Non metallic materials that have ferromagnetic properties

Air Gap

Air space between magnets

Keeper

Used to maintain the strength of magnetic field

Moving electrical charge

Where all magnetic field originates from

Stationary Electrical Charges

Magnetic field does not interact with this

Uniform

Magnetic field inside a solenoid

Current Carrying Wire Loop

Resembles the magnetic field of a bar magnet

North

A current is flowing east along a power line. If the earth’s field is neglected, the direction of the magnet below it is

½ revolution

When a wire loop is rotated in a magnetic field, the direction of the induced emf changes every

Domain

Group of magnetically aligned atoms

Toroid

Electromagnet with its core is in the form of a close magnetic ring

Hall effect

Small voltages generated by a conductor with current in an external magnetic field Effect which is generally used in the gaussmeter to measure flux density

Edison effect

Emission of e- from hot bodies

Wiegand effect

Ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected by a dc magnetic field

Wall Effect

Contribution to the ionization in an ionization chamber by e- from the walls

Bridgman effect

Phenomenon when current passes through an aristropic crystal, there is an absorption of heat due to the non uniformity in current distribution

Hydrogen

Simples atom to exist; it is a diamagnetic material

Germanium

32p+, 32e- and 40n = 72Ge32 = (AtomicWeightGeAtomicnumber)

Atomic Mass

Sum of proton and neutrons (di ko sure pero eto nakalagay e)

Atomic Number

# of protons or # of electrons

72.6

Ge exact atomic weight

28.09

Si exact atomic weight at 300K

# of protons

Determines the atomic # of an element

Copper

34n

Metallic bonding

Atom bonding due to the force of attraction between groups of + ion and – ion

Motor Action

Physical motion resulting from the forces of magnetic field

Flux linkages

= flux x # of turns

Electron Volt (eV)

Customary energy unit in atomic and nuclear physics

Joule, Watt-sec, KW-h

Units of electrical energy

KW-h

Practical unit for electrical energy

Ion

An atom or group of atoms carrying a net electrical charge

Thermionic emission

Evaporation of e- from a heated surface

Amber

Greek word for electron

Plasma

Charged Gases

Exclusion Principle

Principle that states that each e- in an atom must have a different set of quantum numbers

Pauli Exclusion Principle

Principle that states that only 2 e- with differebt spins are allowed to exist in a given orbit

Radio Freq

Common application if an air-cored choke

Ohms Law

For linear circuits (AC,DC)

Crystalline Solid

One of the solid structures in which the position of the atoms or ins are predetermined

Amorphous

Solid with no defined crystal structure; also called non-crystalline

Permits mechanical Clearance

Reason for air gaps between rotor and stator

Van der Waals Bond

Formed when there exist distant electronic interaction between opposite charges present in the neighboring atoms or molecules

Atomic Packing Factor

Measures compactness of crystal = atom volume/cell volume

Madelung Constant

Corrects the electrostatic forces of the more distant ions in an ionic solid

Creepage

Conduction of electricity across the surface of a a dielectric

Aurora

Corona discharge

1.15 to 1.25

Leakage coef for electrical machines

Astrionic

Science of adapting electronics to aerospace flight

Air

Has straight BH curve passing through the origin

Soft iron

BH curve not straight

Using material with narrow hysteresis loop

Reduces hysteresis loss

Silicon steel

Least hysteresis loop area

Unlimited

# of compounds in nature

Ohm-m

SI unit for specific resistance

Siemens / Mhos

SI / CGS for conductance

Siemens/m

SI for conductivity

Resistivity ∞ Temperature

For Conductors

2 Wb/m^2

Typical saturation flux density for most magnetic materials

insulators

Temp coefficient of resistance is NEGATIVE; Temp coefficient of resistance is directly proportional to T; R is inversely proportional to T

semiconductors

Temp coefficient resistance is NEGATIVE

conductors

Temp coefficient resistance is POSITIVE; Temp coefficient of resistance is inversely proportional to T; R is directly proportional to T

Temp coefficient resistance

Dependent on nature and temp of material Tells how much the R changes for a change in T

+ temp coef

Manganin, Tungsten Filament

- temp coef

Electrolytes, carbon

.0034

Temp coef of resistance of pure gold

.0038

Temp coef of resistance of silver

.0039

Temp coef of resistance of lead

Almost 0

Eureka’s Temp coefficient resistance

Silicon Carbibe

Ohms law cannot be applied to this material

10x

Hot R = ___x Cold R

Neutral

A body under ordinary conditions

Dielectric constant or Specific Inductive Capacity

Another name for relative permitivitty

Breakdown Volatage

Another name fore Dielectric Strength (V/mil)

Magnetic conductivity

Another name for permeability

1/(Єoμo) = c2

Relationship of Eo and Uo and c (light velocity)

1 and 10

Dielectric constant of most materials

Mica

Insulating material used in an electric ion

Porcelain

Insulating material used in voltage transformers

Earphones

Uses permanent magnets

Motors

Uses temporary magnets

+ to -

Conventional Flow

- to +

Electron Flow

W

P –true power

VAR

Q – reactive power

VA

S – apparent power

Power factor

Cosθ = P/S

Reactive factor

Sinθ = Q/S

Voltage Magnification Factor

Q Factor of Series resonant circuit

Current Magnification Factor

Q factor of // Resonant Circuit

Voltage Resonance

Series Resonance

Current Resonance

Parallel Resonace

Ionization Current

Results from free electrons

ELI

Series Resonace / Acceptor Circuit

ICE

Parallel Resonance / Rejector Circuit

ELI by exactly 90 deg

Pure inductance

ICE by exactly 90 deg

Pure capacitance

ELI by less than 90 deg

RL

ICE by less than 90 deg

RC

Reactance = 0

If I and V are in phase for an AC circuit

0.707

Current is ____ times the max current at half power points of a resonance curve

Gang Capacitor

Variable Capacitor which the C is varied by varying the plate area

Trimmer Capacitor

A variable capacitor in which C is varied by changing distance between plates

55 ohm-cm

Specific resistance of pure Ge

60 ohm-cm

Resistivity of pure Ge under standard conditions

55 ohm-cm

Specific resistance of pure Si

Leading or Lagging

Power factor of series RLC at its half power points

Leading pf

Capacitive Load

Lagging pf

Inductive Load

Separation of the half power points

Meaning of BW in series RLC

Effective Value

Most important value of a sinewave

Faradic current

An intermittent and non symmetrical alternating current like that obtained from the secondary winding of an induction coil

Stray Capacitance

Capacitance that exists not through design but because 2 conducting surfaces are relatively close to each other

1.73

Peak factor of a triangular wave

Triangular Wave

Peakiest waveform

Independent to each other

Reason for // connection of appliances in homes

Appliances have different current ratings

Reason why not in series connection of appliances in homes

Sinusoidal

Most popular waveform

Square wave

Most common non sinusoidal waveform

Ideal Current Source (parallel r)

Infinite internal resistance Zero internal conductance

Ideal Voltage Source (series r)

Zero internal Resistance Infinite internal conductance

Ideal Ammeter (in series to the circuit)

R is 0

Ideal Voltmeter (in // to the circuit)

R is infinite

Resonance Curve

Frequency VS Current

Reactance Chart

Estimates the resonant freq and to find the reactance at any freq for any value of C or I

Edge Effect

Refers to the outward curving distortion of the lines of force near the edges of 2 // metal plates that form a capacitor

The narrower the passband

(For Series RLC), the higher the Q

Internal Heating

Leakage resistance in a capacitor results to

Phase

The_____ of an alternating quantity is defined as the fractional part of a period or cycle through w/c the quantity has advanced from a selected origin

3.7K

Metal tin becomes a superconductor at this temp

It has a varying magnetic field

Reason why AC can induce voltage

Exponential Law

Charging of capacitor through a resistance obeys _______

Sinewaves

The factor 0.707 for converting peak to rms applies only to _____

CHAPTER2

Joule

Term to express the amount of electrical energy stored in a electrostatic field

Breakdown Voltage

Refers to the lowest voltage across any insulator that can cause current flow

Blocks DC current

Capacitor

47 ohms

Preferred value of resistor (among the choices which are 520, 43K and 54K)

Electrolytic capacitor

Most suited for dc filter circuits; Highest cost per uF; Only Capacitor used in DC circuits; Used in Transistor amplifiers

Variable Capacitor

Used air dielectric

Barium Strontium Titanite Dielectric

Also called ceramic

Surge Voltage

Max voltage that can be applied across a capacitor for a short period of time

Voltage

It is used as the reference phasor for // AC circuits

It has reactance in radio freq circuits

Disadvantage of wirewound resistors

Manganin

Most common material for wirewound

Temp coef

Indicated by the first band for a 5band method of capacitor color coding

Rate at which electrons pas a given point

Determines the magnitude of an electric current

Q of 10

Means that the energy stored in the magnetic field of the coil is 10x the energy wasted in the resistance

770V

Neon lamp ionizes at approx _____

Anticapacitance Switch

Switch designed to have low capacitance between terminals when open

Bifilar Resistor

Resister wound with a wire doubled back on itself to reduce inductance

Alloy

Fusion of elements without chemical action between them

Vpeak

Used in calculating max instantaneous power

Vrms

Used in calculating Vave

Maximum capacitance

Happened when movable plates of gang capacitor overlaps the fixed plates

Thevenin’s Theorem

Used for analysis of Vacuum tubes

Phasor

Rotating vector whose projection can represent either current or voltage

1

# of e- in 4th orbit of copper atom

8 e-

Each atom in a Si Crystal has _____ in its valence orbit

32 p+

Silicon Atom has ____

More slowly

e- in the largest orbit travel _______ than the e- in smaller orbits

Intrinsic semiconductor

Pure Semiconductor

Extrinsic semiconductor

Doped semiconductor; 2 Ohm-cm = resistivity

2mV/°C

For Ge or Si diodes, the barrier potential decreases _____

Piecewise Linear Model

A diode modeling circuit which considers the threshold voltage, Rave and switch as the diode’s equivalent

Diffusion and drift

2 mechanisms by which holes and electrons move through a Si crystal

Diffusion

Random motion due to thermal agitation in the movement of h+ and e- in a Si crystal

Drift Current

Happens when charges are forced to move the electric field of a potential difference

Carrier Drift

Mechanism for carrier motion in semicon

Zener and Avalance Effects

Two possible breakdown mechanism in PN jxn diodes

Zener Breakdown

Electric field in the depletion layer increases to the point where it can break covalent bonds and generate electron-hole pairs

Avalanche Breakdown

(In semiconductors) this takes place when the reverse bias exceeds a certain value; Happens when the minority carriers that cross the depletion region under the influence of the electric field gain sufficient KE to be able to break covalent bonds in atoms

Avalance effect

Occurs are higher reverse voltages

Diffusion or Storage Capacitance

Is the forward bias capacitance of a diode

Lifetime

Amount of time between the creation and disappearance of a free electron

Recombination

Annihilation of e- and h+; Merging of e- and h+

Transit time

Time taken by e- or h+ to pass from emitter to collector

Reverse recovery time

Time taken by a diode to operate in the reverse to forward condition; Time it takes to turn off a FB diode; = storage time + transition interval from F to R bias

Insulator

At room temp, silicon acts like a ______

Compound Semicon

Gallium Arsenide, Alluminum Arsenide and Gallium Phosphide are classified as ______-

Increase electric conductivity

Purpose of adding impurities

Ptype semicon

Silicon doped with trivalent impurity; Holes are majority carriers

Ntype semicon

Silicon doped with pentavalent impurity; Electrons are majority carriers

CHAPTER3

Trivalent Atom

Acceptor Atom; Boron, Indium, Gallium,

Pentavalent Atom

Donor Atom; Phosphorus, Arsenic, Antimony, Bimsuth

N type

Forms when the # of free e- in a doped semiconductor is increased; Forms when pentavalent atom is added

P Type

Forms when the # of free e- in a doped semiconductor is reduced Forms when trivalent atom is added

PN crystal

Other name for Jxn Diode; Commonly rated by its PIV and max forward current; Max forward current is limited by Jxn Temperature

Dipole

Each pair of + and – ions at the jxn is called _____

Barrier Potential

Inversely proportional to temp

High field emission

Creation of free electrons through a zener effect

Intensity of electric field

Zener effect depends on this

Forward current

Most impt diode parameter which gives the current value a diode can handle without burning

Reverse Breakdown Voltage

Maximum reverse voltage that can be applied before current surges

Esaki Diode

Tunnel Diode; Principal char is that it has negative resistance region; Widely used in oscillators, switching networks and pulse generators

Schotty Diode

Most impt application is digital computers

Shocklet Diode

No depletion layer

Bulk resistance

Sum of the P and N regions’ resistances; rB = (V-VT)/I

VAristors

Are transient suppressors

Varactor Diode

Also known as epicap, varicap, voltage-variable capacitance, voltacaps; Used for tuning the Receivers and is normally operated at reverse biased

Point Contact diode

Used metal cat whiskers as its anode; Classified as hot carrier diode

PIN diode

Used in RF switches, attenuators and other phase switching devices

Bulk resistance decreases in semiconductors

If doping increases, ___________

High Resistance

Lightly doped semiconductors have ____

Less than 1 ohm

Typical bulk resistance of rectifier diodes

Transition region capacitance

The reverse bias diode capacitance is termed as ______

LED

Equivalent to a optocoupler ; Typical operating current is 10mA; Voltage drop is 1.5V; Constructed using Gallium Arsenide; Gives light when FB

LAD

A photodiode which conducts current only when FB and is exposed to light; Also called photodiode

IR emitters

Solid state GaAs devices that emit a beam of radiant flux when FB

Optocoupler

Also known as optoisolator

Second approximation

(for diodes) an equivalent ckt of a diode in which it is represented as a switch series with barrier potential

Third approximation

(for diodes) an equivalent ckt of a diode in which it is represented as a switch in series with a resitance

Negative voltage supplies

Needed for PMP voltage divider bias

16.7 ms

Halfwave signal (1/60Hz)

8.33 ms

Fullwave signal (1/120Hz)

40.6%

Max rectification efficiency of HW

81.2

Max rectification efficiency of FW

MOSFET

Highest Zin; Sometimes called Insulated Gate FET

FET

Has least noise level; Has higher Zin compared to BJT due to its input which is reverse biased

uA

Typical leakage current in a PN jxn

Ohms

Resistance of a FB PN jxn

Derating Factor

Shown on a data sheet that tells how much you have to reduce the power of a device

Dember Effect

Or Photodiffusion effect; The creation of voltage in a conductor or semicon by illumination of one surface

Bulk Effect

Effect that occurs within the entire bilk of a semiconductor material rather than a localized jxn

Skin Effect

Increases the resistance of wires at high frequencies

Anotron Diode

A cold cathode glow-discharge diode having a copper anode and a large cathode of sodium or other material

BARITT Diode

A microwave diode in which the carriers that transverse the drift region are generated by minority carrier injection from a FB jxn instead of being extracted from the plasma of avalanche

Spacistor

Multiple terminal solid state device similar to transistor that generates frequencies up to avout 10,000 Mhz by injecting e- or h+ into a space charge layer

Zener Diode

Principal char is that its voltage is constant under conditions of varying current; Used as a voltage regulator or reference voltage

Voltage multiplier

Converts AC to DC, where the DC output can be greater than the AC input

Photoconductive Cell

Or Photoresitive device

Emitter Resistor

Most commonly used for biasing a bipolar jxn transistor

Silicon

Not a good conductor; Has the smallest leakage current

% Ripple

= (Vac / Vdc) x 100

Ripple Voltage

= (rZ / (rZ+rS)) x V

Holes

As a general rule, _____ are found only on semiconductors; An incomplete part of an electron pair bond; Vacancy left by free electrons

Isotopes

A nuclei with common # of p+ but different # of neutrons

Series Capacitors

In power supplies, circuits that are employed in separating AC and DC components and bypass AC components around the load are called _______

Emitter Follower Circuit

Av is low and usually less than 1; Ai is High; input is in-phase with output; Employs 100% negative feedback; Used for impedance matching; Equivalent to CC amplifier

BJT / transistors

Current controlled device; Largest region is the Collector Region

FET

Voltage controlled device; Has 5v pinch off voltage; FET transcoductance = ∆IC/∆VGS ; Square Law Devices; At cut-off, the depletion layers are touching

Transistors

Converts DC power to AC power

Power Transistors

Made in large sized to disspate more heat

Power amplifiers

Input is DC

Oscillators

Converts DC power to AC power

Ohmic

Equivalent if transistor at saturation in JFET is ______

IGFET

Another name for MOSFET

CMOS

Easily damaged by static charges

Saturation region

Used by FET (EMOSFET) to act as an amplifier

Triode region and Saturation Region

Used by FET (EMOSFET) to act as a switch

10uF

Coupling capacitor value in RC coupling; Coupling capacitor (Cc) must be high enough to prevent attenuation of low freq

Qpoint / OperatingPoint

Point of intersection between a diode characteristic and a load line; Intersection of dc and ac load lines

Luminous Efficacy

Measure of the ability of any LED to produce lumens per applied watt of energy

Scale Current

Another name is Saturation Current

Input Char Curve

A graphical representation in a transistor where the IE is plotted against the variable VEB for constant V CB

Output Char Curve

A graphical representation in a transistor where the Ic is plotted against the variable VCB for constant IE

RC coupling

Used in low level, low noise audio amplifiers to minimize hum pick up from stray magnetic fields

Transformer Coupling

Major advantage is permitting power to be transformed from the relatively high output impedance of the first stage to the relatively low input impedance of second stage

1.12eV(Si) and 0.72eV(Ge)

From these conditions, it can be said that less # of electron-hole pair will be generated in Si than in Ge

0.135 m2/V-s

Electron mobility in silicon

Harold Black

Invented feedback amplifier in 1928

Always points to N and away from P

Arrows in semiconductor symbols

CE circuit

Conventional amplifier

Junction and Point Contact

Structural category of a semiconductor diodes

Threshold Voltage

Turns on an enhancement-device

DMOSFET

Acts mostly as a FET; Can operate in D and E

EMOSFET

Can only operate in E

Heat dissipation

Most important factor of a power transistor

Collector Efficiency

Most important consideration in power amplifiers

Drift transistor

Has a high frequency cut off due to its low inherent internal capacitance and low electron transit time

Poor frequency response

Results when transistors are used as video amplifiers

Fission

Break up of nuclei into nuclear fragments that are nuclei themselves

Neutrino

Zero charge and zero mass

EG => 5eV

Energy gap for insulators

EG = 1.1eV

Energy gap for Si semiconductors

EG => 0.67eV

Energy gap for Ge semiconductors

Bound Electrons

Tightly holds the 8 e-

25mV

Thermal Voltage at room temp; Thermal voltage causes holes in intrinsic semiconsuctors

8.62 x 10^-5 eV/K

Boltzman constant

Voltage divider Bias

Preferred form of biasing a FET

VGS(OFF) = VGS(ON)

For N-channel EMOSFET

Beta

CE gain = IC/IB

Alpha

CB gain = IC/IE

CHAPTER5 Collector has reverse bias

Reason why a transistor amplifier has high output impedance

Gain-BW product

Considered as an amplifier figure of merit

Logic probe

In an oscilloscope, it is used to indicate pulse condition in digital logic circuit

Logic analyzer

Used to sample and display systems signal

Oscillators

Produces undamped oscillations

Biasing

Establishes a fixed level of current or voltage in a transistor

AF transformer

It is shielded to prevent induction due to stray magnetic fields

Amplitude Distortion

Or harmonic distortion

Frequency

Ear is not sensitive to this

RC coupling

To separate bias of 1 stage to another stage; Used for voltage amplification; Av is constant over mid frequencies; Most economic type of coupling; Not used to amplify extremely low freq because electrical size of the coupling capacitor becomes very large; Type of coupling used in the initial stage of a multistage amplifier;

Transformer coupling

Used in power amplifiers; Provides high freq because DC resistance is low; Used when load resistance is very low; Type of coupling used in the final stage of an amplifier; Introduces frequency distortion; Most expensive type of coupling; Provides high gain because it employs impedance matching; Can be used either in Voltage or Power amplifiers

DC coupling

Best freq response; Used to amplify dc signals in multistage amplifier; Achieves minimum interference in freq response

Klystron Oscillator

Used in order to produce freq in the microwave region

Step Down Transformer

Used for impedance matching; It is also used as the output transformer in power amplifiers

Gives distorted output

Disadvantage of impedance matching

Campbell and Wagner

Where the basic concept of electric wave filter originated

10Khz

Freq that produces highest noise factor

Coupling Capacitor

The input capacitor in an amplifier

Bigger

AC load line slope is ____ then DC load line slope

At least 2 transistors

Used by multistage amplifier

Generator Output level is kept constant

To obtain the frequency response curve of an amplifier

Relaxation oscillator

Type of oscillator where the frequency is determined by the charge and discharge of RC networks used in conjunction with amplifiers or similar devices

GPS

Instrument used to measure one’s location in terms of coordinates

1/( 4∏√(LC) )

Cutoff freq for constant-k high pass filter

The smaller the %VR

The better!

Thin base

Transistor should have a _____ to have more Av

Darlington Pair

Its advantage is that it increases overall Beta Gain

Independent

A feedback network is _______ of frequency

Feedback Networks

They employ resistive networks

Positive Feedback

Employed by Oscillators;

Negative Feedback

Employed by amplifiers Reduces distortion; Reduces gain; Increases BW of an amplifier; The sacrifice factor is (1+Aβ)

Feedback factor (β)

Is always less than 1; = (1/Af) – (1/A) = Vf / V

Approx gain of an amplifier with negative feedback (Af)

Reciprocal of feedback factor; = 1/β

(Aβ) in negative feedback

Very much greater than 1 to obtain good gain stability

Power Again (Ap)

= Av x Ai; Main consideration in the output stage of an amplifier

Crossover network

A pair of filter common on a high fidelity system which separates audio freq band signals into 2 separate groups where one is fed to the tweeter and the other to the woofer

Armstrong circuit

Simplest variable freq sinusoidal oscillator

10uF

Typical value of Coupling capacitor

50uF

Typical value of emitter bypass capacitor in a CE multistage amplifier

Re, re and β

Input R of CE amplifier is affected by ________

Out of phase (180 deg)

Output is always _______ with the input signal in a CE amplifier

Zero

Phase difference between collector voltage and signal voltage in CE amplifier

Increase Av

Purpose of emitter bypass capacitor in CE amplifier is to _____

LC oscillator

Used only in/for high freq

RC Oscillator

Used only in/for low freq

Sine wave oscillator

Composed of 1 or more amplifying devices with some freq determining networks introducing + feedback

Hartley Oscillator

Used commonly in Radio Rx

Crystal Oscillator

Used commonly in Radio Tx; Fixed frequency oscillator; Has fewer loses and will generate alternating emf longer than LC circuit when shock excited

Tuned Amplifier

Operated in Class C; Used in Radio freq

Wien Bridge Oscillator

Frequency stability of the oscillator output is maximum ________; Employs both + and – feedback; Used in signal generators in laboratories;

Hum in the circuit

A pulsating DC applied to the power amplifier causes ______

Low Output

Important limitation of Crystal Oscillator

High Q

Reason why crystal oscillator freq is very stable

More than 10,000

Typical Q of a crystal

Push Pull amplifer

Commonly employed at the output stage of an amplifier

X axis

Cutting perpendicular to end to end; Electrical axis; Connects the corners of the crystal

Y axis

Cutting perpendicular to face to face; Mechanical

+ temp coef

When crystal freq increases with temp

- temp coef

When crystal freq decreases with temp

Zero temp coef

When crystal freq doesn’t change with temp

More battery consumption

Low efficiency of a power amplifier results in ______

Buffer Amplifier

Used for minimum loading and minimum mismatch

Hand capacitance

If you move towards an oscillating circuit, its freq changes because of the ______

Ic becomes maximum

When transistor is at saturation

Maximum voltage appears across transistor

When transistor is at cut-off

At minimum

In an LC circuit, when the Capacitor energy is at max, the inductor energy is _____

AC load line

The operating point in a transistor amplifier moves along ______ when AC signal is applied

Power stage

Also called output stage in an amplifier

DC

At zero signal conditions, a transistor sees _____ load

Sum of AC and DC

The current in any branch of a transistor amplifier that is operating is the _____

CMRR = infinity

For an ideal differential amplifier

To set up an operating point

The purpose of dc conditions in a transistor is _____

To avoid drop in gain

The purpose of an emitter capacitor is _____

Collector Supply

The Poutput of a transistor amplifier is more than the Pinput due to the additional power supplied by _______

Low

When a transistor feeds a load of low R, its Av is _____

25%

Max collector efficiency of Resistance Loaded Class A power amp

50%

Max collector efficiency of Transformer coupled Class A power amp

RF amplifiers

Class C amplifiers are used as

Driver stage

Employs class A amplifiers

1NPN, 1PNP transistor

Complementary-symmetry amplifier

Increases Input Impedance, Decreases Output Impedance

Negative voltage feedback

Decreases Input Impedance, Increases Output Impedance

Negative Current Feedback

ID

The Quiescent current of a FET amplifier is _____

AND gate

The frequency response of the combined amplifier can be compared with an ______