Experiment

  

Figure 5.7: Basic Op-Amp

1.

Set up the circuit in Fig.5.7.

2.

Measure the DC values at the points indicated with an 'X'. Calculate the values theoretically and compare them with the measured ones.

3.

Input a sine wave of amplitude 0.03V into Q1. at a frequency of about 50KHz. Measure the open loop voltage gain A_dm. Calculate the theoretical value for the gain and compare it to the measured result.

4.

By varying the amplitude of the input signal, measure the maximum swing of the circuit. What happens at the output when the input signal becomes too large.

5.

By driving several different resistor loads ranging from $100\Omega$, to 100K, determine the output resistance of this circuit. Compare your measured value with the theoretical one. Also, compare the measured value here with the measured value of the diff-amp in the previous experiment.

6.

Connect the feedback as indicated in Fig. (5.5). Use resistance values of 10K and 1K for R_F1 and R_F2 respectively, and a $0.1\mu f$.Measure the voltage gain and decide if it can be represented by equation (5.35).

7.

By driving various loads like you did above, try to determine the output resistance of the circuit with feedback. How does feedback affect R_o?