AMP_RC_T.SHOT_PWM

A detailed illustration of a push-pull amplifier circuit showcasing its components, including transistors, capacitors, and transformers, with labels indicating different parts and their fun<wbr>ctions, in a colorful and engaging style.

Understanding Push-Pull Amplifiers Quiz

Test your knowledge of push-pull amplifiers and their properties with this comprehensive quiz! Designed for enthusiasts and students alike, this quiz will challenge your understanding of circuits, amplifier classes, and various coupling methods.

Topics covered include:

Amplifier classes (A, B, AB)
Crossover distortion
Transformer coupling
Coupling methods (RC, direct, transformer)

48 Questions12 MinutesCreated by AmplifyingSignal42

The push-pull circuit needs two signals that are _____

in phase and equal in magnitude

in phase and unequal in magnitude

180° out of phase and equal in magnitude

180° out of phase and unequal in magnitude

What should be there at the circuit input to obtain the signals mentioned in the previous question?

a phase splitter circuit

a transformer with a center tap

a transformer without a center tap

Either a. Or b.

The crossover distortion in the procedure was caused by _____

an increase in the amplitude of the input signal

The removal of the dc bias of the circuit.

An increase in total de circuit current.

The removal of the center tap of transformer T

If class B amplifiers dissipate less power than class AB amplifiers, why do some push-pull circuits use class AB amplifiers?

Two class AB amplifiers require a smaller dc power supply

Two class B amplifiers can cause distortion at the zero crossing

Class B amplifiers cannot be used back-to-back

Class AB amplifiers have a lower base-emitter voltage drop

If the ac input signal (Vi) is zero for the class AB push-pull circuit, the ac base _____

currents of both Q1 and Q2 are zero

Current of Q1 is zero

current of Q2 is zero

Currents of both Q1 and Q2 are equal to the dc base currents

How are the two transistors in a push-pull class AB circuit biased?

They are in the center of the load line

One is near cut-off, the other is near saturation

They are both near cut-off

They are both near saturation

If the dc bias is removed from a push-pull class AB circuit, _____

the output goes to zero volts

The peaks and valleys of the output will be clipped

cross-over distortion occurs

None of the above.

In a class AB push-pull amplifier, voltage gain _____

Is high and power gain is low

Is low and power gain is high

and power gain are high

and power gain are low

For how many degrees of the input signal a class AB amplifier conducts ?

90° or less

between 90° and 180°

between 180° and 360°

almost 360°

The output transformer in a push-pull amplifier _____

combines the two collector signals into one output signal

matches the circuit to the low impedance load

furnishes a dc path for the collector supply voltage

All of the above

In class A operation, the operating point is generally located at _____ point of the DC load line

cut off

the middle

saturation

any point

What turn ratio (Np/Ns) of transformer is required to match 2 Ω speaker to a transistor having an output impedance of 301 Ω? HINT: RL`=Ratio^2*RL

6.12

A BJT class B push-pull amplifier with no transformer coupling uses

two NPN transistors

two PNP transistors

complementary transistors

none of these

Crossover distortion is a problem for _____

class A amplifiers

class AB amplifiers

class B amplifiers

Common-base amplifiers

The maximum efficiency of a class AB amplifier is _____

higher than a class B

the same as a class B

about the same as a class A

Slightly less than a class B

The use of a by-pass capacitor in CE amplifier is …*

To increase voltage gain

To increase negative feedback

For decreasing the frequency

To block dc

The purpose of capacitors in a transistor amplifier is ...*

To protect the transistor

To cool the transistor

To couple or bypass ac component

To provide biasing

In an RC coupling scheme, the coupling capacitor CC must be large enough .....*

To pass DC between the stages

Not to attenuate the low frequencies

To dissipate high power

None of the above

The purpose of RC or transformer coupling is ...*

Block AC

Separate bias of one stage from another

Increase thermal stability

None of the above

If a three-stage amplifier has individual stage gains of 10db, 6db and 15db; then the total gain in dB is*

600dbB

24dB

14dB

31dB

The cascading of two transistor amplifiers implies...*

Output of first stage sent to input of second stage

Output of first stage sent to coupling device

Input of first stage sent to input of second stage

None of the above

The reason why RC coupling is not used to amplify extremely low frequencies is ...*

There is considerable power loss

Electrical size of coupling capacitor becomes very large

There is a hum in the output

Electrical size of coupling capacitor becomes very small

RC coupling is generally confined to low power applications because of ………*

Large value of coupling capacitor

Low efficiency

Large number of components

None of the above

The bandwidth of a single stage amplifier is …………. That of a multistage amplifier*

More than

The same

Less than

other

In PWM, the ______ of pulse width modulator is varied and controlled by the input audio signal amplitude.*

Amplitude

position

width

none of the above

In PPM, the ______ of pulse width modulator is varied and controlled by the input audio signal amplitude.*

Amplitude

position

width

none of the above

In PWM, as the amplitude of the audio signal is increasing the pulse width will become ________.*

narrower

wider

fixed

none of the above

In PAM, the ______ of pulse width modulator is varied and controlled by the input audio signal amplitude.*

Amplitude

position

width

none of the above

What is the usage of the first LM555 in LM555 PWM circuit*

Astable multivibrator

Monostable multivibrator

Stable multivibrator

None of the above

What is the usage of the second LM555 in LM555 PWM circuit*

Astable multivibrator

Monostable multivibrator

Stable multivibrator

None of the above

In product detector PWM demodulator, the multiplication circuit is followed by*

Low pass filter

High pass filter

Band pass filter

Band reject filter

In UA741 PWM circuit, if the input terminal is grounded, what is the output found in the output terminal*

Option 1

Option 2

Option 3

Option 4

MC1496 PWM demodulator circuit base idea is*

convert to PAM signal and demodulate

convert to PPM signal and demodulate

product detector

none of the above

Pulse width of Monostable multivibrator is*

.693 (R_1+R_2 ) C_1

.693 (R_1+2R_2 ) C_1

.693 (R_2 ) C_1

1.1 (R_1 ) C_1

What are the functions of VR1 in UA741 PWM circuit?*

Control reference voltage of comparator

Control negative feedback voltage

a charge/discharge path

none of the above

LM555 can be used in constructing a _________*

Astable multivibrator

Monostable multivibrator

Stable multivibrator

All the above

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