Differential amplifier circuit experiment

Experiment 5 Differential amplifier circuit experiment

1. The purpose of the experiment

1. Master the test method of differential amplifier circuit principle and main technical indicators

2. Familiar with the performance difference between the basic differential amplifier circuit and the differential amplifier circuit with a mirrored constant current source, and clear measures to improve performance

2. Experimental equipment

1. One oscilloscope. 2. One signal source. 3. One millivolt meter. 4. One DC power supply. 5. One digital multimeter. 6. Several resistors, capacitors and crystal transistors.

3. Experimental principle

1. Differential amplifier circuit

5. Replace Re with a constant current source:

Due to the AC equivalent resistance of the constant current source >> Re

4. Experimental content:

1. Connect the experimental circuit according to the schematic diagram. Note: Power connection

2. Measurement of static operating point.

3. Measurement of differential mode voltage magnification. When measuring VOPP, since VO1PP and VO1PP are inverted, the oscilloscope CH1 is superimposed and CH2 is inverted.

4. Measurement of common mode voltage magnification. When measuring VOPP, since VO1PP and VO1PP are in phase, the oscilloscope CH1 is superimposed and CH2 does not need to be inverted.

5. Measurement of differential mode voltage magnification with constant current source. Adjust Rp2 to make Vc1 and Vc2 equal to the values ​​in Table 1.

6. Measurement of common mode voltage magnification with constant current source.

V. Reporting requirements (refer to textbook requirements)

1. Organize the data and process it. 2. According to the test results, explain the differences and causes of the circuit performance of the two differential amplifier circuits. 3. Answer the thinking questions.

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