[Tianjin University of Technology] Differential amplifier circuit + Wang Heping

Question requirements

1. Basic requirements

(1) Build a triode differential amplifier circuit according to the circuit shown in Figure 2, and debug it to make it work normally. The transistor uses 9013. (

(2) Design a differential signal source to test the performance of the amplifier produced, and generate 2 differential signals for testing. Uid meets the following requirements:

               a) Common mode signal voltage range: 0V~1V, 10mV step;

Work description:

The differential amplifier circuit tester is a test system based on the DDS module as a signal generator. It includes STM32F103ZET6 and DDS signal source modules, integrated operational amplifier modules, transistor differential amplification circuit modules, and OLED display modules. The DDS signal source module is composed of the main control microcontroller STM32F103ZET6 and the DDS module. It can generate common-mode signals with adjustable amplitude and differential-mode signals with adjustable amplitude and frequency, and send the signals to the integrated operational amplifier module through the I/O port . Through the power module, its isolation characteristics are applied to generate +5V and -5V voltages to power the LF347 integrated operational amplifier module . The signal passes through the integrated operational amplifier module, which amplifies the signal while converting the single signal into two reverse differential mode signals, which are input to the triode differential amplification circuit. The output signal is fed back to the microcontroller, and the OLED display on the microcontroller displays the difference. Amplify the amplitude-frequency characteristics of the circuit and calculate the cut-off frequency. This tester has good performance and can better realize the functions required by the question.