Willy Nilly, a peripatetic EE grad student, has a problem. He has been trying to help his advisor set up an op-amp experiment. Here is what he has done, step-by-step.
1. He set up a function generator to provide a sine wave at 1000 Hz.
2. Using an oscilloscope, he carefully set the sine wave to have an amplitude of 0.10v (0.20v peak-to-peak).
3. He wants to demonstrate an operational amplifier circuit with a high gain, so he wired up the circuit below.
The values he chose were:
R1 = 50W.According to his calculations this gives a gain of -100.
R0 = 5000W.
4. He calculates that with a gain of -100, he should get an output signal that is 10v amplitude (20v peak-to-peak).Willy is at a loss. He has repeated all of the above steps several times, and he cannot understand why the output is not what he expects it to be.
5. He measures the output of the operational amplifier. The measured signal is 5v amplitude (10v peak-to-peak). This is not what he expected!
6. Although the output of the operational amplifier is not what he expected, the input and output voltages are 180o out of phase, as expected.
Your problem: You need to explain to Willy what is going on.
You will probably want to connect the circuit in lab to see if he observed
things correctly before you draw any rash conclusions.