Question

In the circuit shown in the following Figure, what is the output voltage (\( V_{out} \)) if a silicon transistor Q and an ideal op-amp are used?

• A. -15 V
• B. -0.7 V
• C. +0.7 V
• D. +15 V

Hint:

In op-amp circuits with feedback, the output voltage often follows the input transistor's characteristics, like the base-emitter voltage of 0.7V for silicon transistors.

Answer 1

The Correct Option is B

- In the given circuit, the op-amp is configured as a feedback amplifier. The silicon transistor Q operates with a base-emitter voltage of approximately 0.7V. - With the ideal op-amp, the inverting input is held at the same potential as the non-inverting input (virtual ground condition), and the transistor Q will have a collector-emitter voltage of about -0.7V. Thus, the output voltage \( V_{out} \) is -0.7V. Therefore, the correct answer is option (2).