Aiming at the measurement method of electrical capacitance tomography, a set of micro-capacitance acquisition system for planar array capacitance sensor is designed. Using the circuit principle design of high sensitivity and anti-interference, a dual-channel signal generator with adjustable amplitude and phase was designed to excite the capacitance sensor. The core capacitance voltage conversion circuit of the acquisition system adopts an AC excitation type conversion circuit with the ability to resist stray capacitance interference, and analyzes the error influencing factors in combination with the actual circuit components. The array control switch group is designed for multi-channel switching acquisition, and optimized in conjunction with the capacitor voltage conversion circuit. For the phase demodulation method, an orthogonal optimization method based on hardware multiplier is proposed. A micro-capacitor experiment is designed to calibrate the acquisition circuit. The experimental results show that the capacitance acquisition resolution of the micro-capacitor acquisition system within the acquisition range is 2.84fF, the linearity is 0.9998, and the acquisition error is less than 0.12fF.

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Traditional frequency power and test equipment cannot meet the requirements. This paper discusses in detail the composition of FM type series resonance test device, technical principles, characteristics and advantages. And also introduces wiring method, test methods, test standard. The instance proves that discharge test of large transformer using the FM series resonance device is convenient and accurate.