Design and Manufacture of Gain Adjustable Broadband Amplifier

In this paper, the design and fabrication method of a gain adjustable wide-band amplifier is presented. The amplifier circuit is mainly composed of two programmable amplifier AD8370, and the control part is composed of AT89C52 single-chip microcomputer, keyboard and LCD display. The gain control information is input through the keyboard, and the gain of the two-stage amplifier is controlled by the single-chip microcomputer, and the gain value is displayed on the LCD1602 LCD screen. This design uses a variety of measures to improve the stability of the amplifier, reduce the circuit noise and suppress the high frequency self-excitation, and maximize the bandwidth and gain. The experimental results show that the output waveform of the amplifier is stable, the noise voltage is small and the gain fluctuation in the frequency band is small.