A Cascaded Linear High-Voltage Amplifier Circuit for Dielectric Measurement

Abstract

High-voltage amplifiers have the features of high output voltage, wide frequency bandwidth, and desirable linearity. It is widely used for dielectric measurement in industrial and laboratory applications. This paper presents a new type of cascaded high-voltage amplifier with a voltage gain of 40 times for one circuit cell. The unit circuit is given in detail, which is based on an isolation circuit with linear opto-coupler and an amplified circuit with six operational amplifiers. The negative feedback and capacitive loads characteristics are analyzed theoretically. The step response and frequency curves for two units of amplifier circuit have been tested physically in laboratory. The test results show that the expected voltage gain within the frequency range from 10^-3 to 10⁴ can be obtained accurately. The new type of linear high-voltage amplifier circuit proposed in this paper is also helpful to insulation diagnosis, electrostatic deflection, and other industrial applications.