An ideal OPAMP is used to make an inverting amplifier. The two input terminals of the OPAMP are at the same potential because,
- A. the two input terminals are directly shorted internally
- B. the open loop gain of the OPAMP is infinity and CMRR is infinity
- C. the input impedance of the OPAMP is infinity
- D. slew rate is very high
Answer: B. the open loop gain of the OPAMP is infinity and CMRR is infinity
Explanation: Virtual short/ground concept: Since the open loop gain A → ∞ (and CMRR is infinite), the differential input voltage Vd = Vo/A = 0, so both input terminals are at the same potential.