Question

We intend to measure the open-loop gain (A open ) of an actual operational amplifier. The magnitude of A_open is in the range of 10^6 V/V. However, the signal generator in measurement setup can supply minimal voltage of 1 mV, and the oscilloscope used at amplifier output can measure maximal voltage level of 10 V. Can you design a simple measurement setup using this signal generator and oscilloscope, and accurately measure the A_open?

Answer 1

Answer:

circuit diagram is attached below

Explanation:

Magnitude of A_ open = 10^6 v/v

Vp = Vin / 1001

where: Vin = 1 mV.

hence Vp = 1 mV / 1001  ≅  1 μ V

while Vout = Aopen( Vp )

                ∴ Aopen = Vout / Vp

since Vp = 1 μV then we can can measure Aopen with Vout ranging up to

10 V

attached below is the measuring circuit for measuring open loop gain of amplifier