Question

In an astable multivibrator using an op-amp, the feedback factor is 0.5 and the supply voltage is ±12V. What are the quasi-stable output state and the input to the non-inverting terminal?

(a) Quasi-stable output = ±12V, Input to non inverting terminal = ±12V

(b) Quasi-stable output = ±6V, Input to non inverting terminal = ±12V

(c) Quasi-stable output = ±12V, Input to non inverting terminal = ±6V

(d) Quasi-stable output = ±12V, Input to non inverting terminal = 0V

The question was posed to me in an interview.

Origin of the question is Different Types of Multivibrators topic in portion Multivibrators of Analog Circuits

Answer 1

The correct answer is (c) Quasi-stable output = ±12V, Input to non inverting terminal = ±6V

The best explanation: Quasi-stable output = ±VSat = ± VSupply = ±12V

Input to non inverting terminal = ±βVSat = ±6V.