RLC Measuring Circuits Based on Free-Axis Method

A kind of universal measuring circuit for resistance,inductance and capacitance is designed,the principle is based on volt-ampere method for impedance measurement,and the phase referenced benchmark is determined by free-axis method.Concerning the small capacitance(under 2pF),the parallel-connection equivalent mode is adopted,and as to the large capacitance(above 2pF),the series-connection equivalent mode is adopted.Powered rectifier input of the former is connected to the half-bridge voltage branch A1,and the oscillator supplies the half-bridge circuit with an invariable voltage sine signal.While powered rectifier input of the latter is connected to the half-bridge voltage branch A2,and the oscillator supplies the half-bridge circuit with an invariable current sine signal.