Design of Variable Gain Amplifier Circuit Based on Newton Rings Stress

Abstract

Abstract--On the purpose of measuring Newton rings deformation stress and the intelligentialize of the newton rings apparatus, a Variable Gain Amplifier circuit which is based on a low power, general purpose instrumentation amplifiers INA128 offering excellent accuracy was designed to amplify the low frequency and voltage signal from the Pressure sensor. The principle of circuit and the information of chips used were introduced detailedly. Intermediately, problem which appeared in the program of the design had been figured out. Finally, test the performance of the circuit and analyze the experimental data with MATLAB, results were as follws, when the gain is equal to 33.97dB(Magnified 50 times),the bandwidth is up to 599kHz; when the gain is equal to 40dB(Magnified 100 times),the bandwidth is up to 250kHz; when the gain is equal to 53.98dB(Magnified 500 times),the bandwidth is up to 39kHz. key words-gain variable; Amplifier circuit; nstrumentation; newton rings;INA128.