JEE Main 202226 JuneEvening Shift
- Exam
- JEE Main
- Year
- 2022
- Date
- 26 June
- Shift
- Evening Shift
- Subject
- Physics
- Chapter
- Semiconductors
JEE Main 2022 · 26 June · Evening Shift · Physics · Semiconductors
The positive feedback is required by an amplifier to act as an...
The positive feedback is required by an amplifier to act as an oscillator. The feedback here means
Options
- AExternal input is necessary to sustain ac signal in output.
- BA portion of the output power is returned back to the input.
- CFeedback can be achieved by LR network.
- DThe base-collector junction must be forward biased.
Correct answer
B. A portion of the output power is returned back to the input.
Step-by-step solution
When the amplifier connects with positive feedback, it acts as the oscillator. The feedback employed here is positive feedback, this means some amount of the output voltage is given to the input. Hence, the circuit continues its process without any input to the oscillator. The positive feedback is also known as regenerative feedback because the system sustains or regenerates itself without any input source. Hence, the oscillator is nothing but an amplifier with the positive feedback.