CET Staging & Prognostic Factors 2 — Questions and Answers
Question 1: In a two-stage RC-coupled amplifier, if each stage has a voltage gain of 20, what is the overall voltage gain?
- 40
- 400 (Correct answer)
- 200
- 20
Correct answer: 400
Voltage gains of cascaded stages multiply, so 20 × 20 = 400.
Question 2: Which coupling method between amplifier stages passes DC as well as AC signals?
- RC coupling
- Transformer coupling
- Direct coupling (Correct answer)
- Capacitive coupling
Correct answer: Direct coupling
Direct coupling connects stages without capacitors or transformers, passing both DC and AC components.
Question 3: What is the primary purpose of an emitter bypass capacitor in a transistor amplifier stage?
- Increase DC stability
- Prevent oscillation
- Increase AC voltage gain (Correct answer)
- Reduce collector current
Correct answer: Increase AC voltage gain
The bypass capacitor shorts the emitter resistor at AC frequencies, removing negative feedback and increasing AC gain.
Question 4: In a multistage amplifier, the overall bandwidth compared to a single stage is:
- The same
- Greater
- Narrower (Correct answer)
- Dependent only on the last stage
Correct answer: Narrower
Each additional stage further limits the bandwidth, making the overall bandwidth narrower than any single stage.
Question 5: What does the term 'interstage coupling' refer to in amplifier design?
- Feedback from output to input
- Method of connecting one amplifier stage to the next (Correct answer)
- Impedance matching at the antenna
- Power supply decoupling
Correct answer: Method of connecting one amplifier stage to the next
Interstage coupling refers to the method (RC, transformer, or direct) used to connect successive amplifier stages.
Question 6: When using transformer coupling between stages, what key advantage does it provide over RC coupling?
- Lower cost
- Better high-frequency response
- Impedance matching between stages (Correct answer)
- Simpler circuit design
Correct answer: Impedance matching between stages
Transformer coupling allows impedance transformation between stages, maximizing power transfer.
Question 7: In decibel notation, a two-stage amplifier with each stage providing 20 dB gain has a total gain of:
- 40 dB (Correct answer)
- 400 dB
- 200 dB
- 20 dB
Correct answer: 40 dB
In decibels, gains of cascaded stages are added: 20 dB + 20 dB = 40 dB.
CET Staging & Prognostic Factors 2
In a two-stage RC-coupled amplifier, if each stage has a voltage gain of 20, what is the overall voltage gain?