Topic: Analog Circuits
In transistor oscillators, FET and BJT are used. Instability is achieved by:
- A. Negative feedback
- B. Positive feedback
- C. Using a tank circuit
- D. None of the above
Answer: B. Positive feedback
Explanation: To initiate and sustain oscillations, a transistor oscillator requires an unstable state. This instability is achieved by using positive feedback, where a portion of the output signal is fed back to the input in phase with the original signal, satisfying the Barkhausen criterion.