Development of a wide-range sampling impedance ratio bridge

This paper describes an automated high-accuracy impedance bridge for the comparison of resistors, inductors or capacitors in the range between 1 mΩ and 100 MΩ over a frequency range of 10 Hz to 20 kHz. The bridge consists of a high resolution digitizer and a six-channel digital waveform generator. A solid state multiplexer has been made to switch between the various positions in the bridge and to utilize the linearity of the digitizer for the determination of the complex ratio of the two impedances under test. A special mode of operation allows the comparison of current shunts.