Download Amplifier Circuits Quiz - e-VET

Amplifier basics QUIZ
1.
If a power amplifier produces an output 10 times greater than its input, what will its power gain be,
measured in deciBels?

a) 3dB

b) 6dB

c) 10dB

d) 20dB
2.
If the base current Ib of a common emitter amplifier is 40µA and the hfe of the transistor is 200, what
will the collector current?

a) 240µA

b) 800µA

c) 25µA

d) 8mA
3.
In Fig 1.5.1 what is the purpose of block B?

a) A Tuned RF amplifier

b) An FM amplifier

c) An IF amplifier

d) An AF pre-amplifier
4.
Which of these formulae gives the voltage gain of an amplifier?

a) Vout/ Vin

b) Vin/ Vout

c) Vout/ Iin

d) d) Vin x hfe
5.
Complete this sentence: "Class A bias...

a) ...gives high gain and low distortion".

b) ...gives high gain and low distortion".

c) ...gives low distortion and low efficiency".

d) ...gives low distortion and low gain".
6.
Complete this sentence: "Class A bias sets the quiescent current...

a) ...below cut off".

b) ...above cut off".

c) ...at Ib = 0".

d) ...at cut off".
7.
What is the voltage gain of an amplifier at the half power points on the amplifier response curve?

a) 0.5

b) 0.707

c) 1.414

d) 6.0
8.
What is the purpose of C3 in Fig 1.5.2?

a) To prevent HF noise.

b) To prevent saturation.

c) To prevent thermal runaway.

d) d)To prevent negative feedback.
9.
In Fig 1.5.2 which component will be mainly responsible for limiting high frequency gain?

a) Tr1

b) C2

c) C3

d) C4
10.
What is the advantage of extending the bandwidth of audio amplifiers to frequencies higher than the
audible limit?

a) To reduce noise.

b) To increase efficiency.

c) To preserve wave shape.

d) To reduce transients.
Amplifier Circuits Quiz
Try our quiz, based on the information you can find in Amplifiers
Module 4. Submit your answers and see how many you get right. If
you get any answers wrong. Just follow the hints to find the right
answer and learn about Amplifiers as you go.
1.
What would be the function of the control circuit shown in Fig. 4.4.1 in an audio amplifier?

a) Volume.

b) Balance.

c) Treble boost.

d) Tone.
2.
What is the purpose of RIAA de-emphasis in an audio pre-amplifier?

a) To provide correct impedance matching on a MIC input.

b) To provide D to A conversion on a CD input.

c) To provide frequency correction on a PHONO input.

d) To provide level correction on a line level output.
3.
When the bass and treble controls in a Baxandall passive tone control circuit are set at their mid
point, what will be the approximate voltage gain of the tone control circuit?

a) -3dB

b) -6dB

c) -20dB

d) -40dB
4.
Complete the following sentence: Compared with a bipolar transistor, using a JFET transistor in the
input stage of an audio amplifier instead of a bipolar transistor provides...

a) ...higher input impedance and reduced signal to noise ratio.

b) ...higher input impedance and increased signal to noise ratio.

c) ...higher gain and increased signal to noise ratio.

d) ...higher gain and reduced signal to noise ratio.
5.
Bootstrapping in an amplifier circuit refers to which of the following techniques?

a) Using positive feedback to increase the apparent input impedance of the
amplifier.

b) Using negative feedback to increase the apparent input impedance of the
amplifier.

c) Using negative feedback to reduce the apparent output impedance of the
amplifier.

d) Using positive feedback to increase the stability of the amplifier.
6.
Which of the following features does the circuit illustrated in Fig. 4.4.2 posess?

a) High voltage gain and very high input impedance.

b) Low voltage gain and very high output impedance.

c) High current gain and very high input impedance.

d) Low current gain and very high output impedance.
7.
Which of the following would be a typical value for the input impedance of a common collector
amplifier?

a) 1KΩ

b) 15KΩ

c) 150KΩ

d) 15MΩ
8.
Refer to Fig 4.4.3. If the real value of R3 is 33KΩ and the open loop gain of the emitter follower
amplifier (AO) is 0.98, what will be the apparent value R3?

a) 1.65MΩ

b) 2.35MΩ

c) 3.27MΩ

d) 230.5KΩ