Experiment: Realistic Op-Amp

The circuit below (6.3) represents the internal design of a basic typical op-amp.

1.

Construct the circuit. Adjust the pot so V_o=0 for V_in=0

2.

See if you can measure the open loop gain at 10kHZ.

3.

Attach a feedback circuit to give a midband gain of -10 (inverting). Measure the gain as a function of frequency ranging from 100Hz to 1MHz. (Try using 10k and 1k resistors).

4.

Attach a feedback circuit to give a midband gain of 11 (noninverting). Measure the gain as a function of frequency ranging from 100Hz to 1MHz.

5.

This circuit may oscillate spontaneously. If it does, add a compensation capacitor at the collector of Q5.

  

Figure 6.3: Realistic Op-Amp