Exam-style question
Try this first
A signal of 1 V peak is applied to the input of an ideal inverting amplifier with a voltage gain of –5. What will be the phase relationship between the input and output signals? Explain the reason for this relationship.
Model answer
What a good answer should say
- The output will be 5 V peak and 180° out of phase with the input.
- The negative sign in the gain indicates that the output voltage changes in the opposite direction to the input, which is a consequence of the op‑amp’s inverting configuration and the requirement of negative feedback to maintain the virtual short.
Explanation
Why this works
The answer demonstrates that the student recognises the negative gain as a phase inversion and explains the underlying op‑amp mechanism. It tests the ability to link numerical gain to phase behaviour.
Common mistake
No common mistake is linked to this question yet.