The output voltage of an operational amplifier is ?
- A. 90 degree out of phase from the input.
- B. 180 degree out of phase from the input.
- C. 45 degree out of phase from the input.
- D. –90 degree out of phase from the input.
Answer: B. 180 degree out of phase from the input.
Explanation: Taken as the inverting configuration: output is 180° out of phase. Verify against the key.