Research on the Detecting Technology of Tiny Capacitance

The detection technology of extremely small capacitance is mainly divided into analog circuit detection mode based on discrete components and capacitance detection circuit based on special integrated chips. The analog circuit has the limitations of poor anti interference ability and complex design. With the maturity of digital processing circuit and the development of MEMS technology, based on the calculation requirements of the capacitance sensor of a certain type of high-precision laser pointing controller, the detection technology of extremely small capacitance is studied. First, three aspects of core device are chosen and analyzed. Then, circuit hardware and software are designed. Finally, experiments are tested and verified. The measured results show that the system can meet the detection requirements of measuring range from 1pF to 30pF and resolution of 1.4fF at 1kHz sampling rate.