Sinusoidal Excited Direct Digitizer Circuit for Measurement of Inductance and Resistance
Philip V. Noel · 2019
This paper details the design of a sinusoidal excited direct digitizer circuit for measuring inductance and resistance values of inductive elements. The conversion technique uses a modified dual-slope scheme. A sinusoidal voltage is provided to a voltage to current converter, which is then applied across the inductive element or coil whose inductance and resistance is to be measured. The voltage developed across the unknown element is then applied to the front end of a modified dual-slope converter. The output is a digital representation of the coil inductance and resistance, and is linear over the entire range of measurement. The digital output is generated without the use of Analog-to-Digital converters (ADC) or additional rectifier circuits. The conversion technique is insensitive to most of the circuit parameters and provides excellent accuracy of measurement. Simulation of the proposed digitizer indicates an overall error within 0.09% for both inductance measurement and resistance measurement.