A Novel LCR Impedance Detection System with Low Cost and High Precision Based on Microcontroller Unit

Inductance-capacitance-resistance (LCR) impedance detection system is an important instrument for measuring object impedance, which is widely used in all kinds of testing products, with the characteristics of high precision and wide measurement range. With the continuous enrichment of impedance measurement scenes, impedance detection is becoming more and more embedded. It is of great significance to use MCU and automatic balanced bridge method to design a low-cost and miniaturized impedance detection system. In this paper, the LCR impedance detection system is built by using capacitors, resistors, inductors, MCU, operational amplifiers, analog switches and other devices, which has the advantage of low cost. The ADC and DAC peripherals built in MCU are used for signal conversion, the FFT operation realized by software is used to obtain amplitude and phase, and a single power supply is used at the same time, which further reduces the cost, makes the system more miniaturized, and meets the requirements of measuring speed, frequency and high precision.