A 200-Hz to 30-MHz Computer-Operated Impedance/Admittance Bridge (COZY)

A 200-Hz to 30-MHz Computer-Operated Impedance/Admittance Bridge (COZY) By L. D. WHITE, R. W. C O O N S , a n d R. C. S T R U M (Manuscript received September 12, 1980) the past few years the development of ferromagnetic compoparticularly for long-haul transmission systems, has relied on large numbers of highly accurate impedance measuremade on a computer-operated impedance/admittance bridge (COZY) developed especially for this work, COZY's accuracy and speed enable a level of component development not otherwise possible, COZY automatically measures complex impedance, temperature coefficients of complex impedance, and disaccommodation factors of ferromagnetic materials, providing accuracies of ±0.05percent for inductance, ±50 microradian for loss angle, and ±10 parts per million for the small impedance changes associated with determinations of temperature coefficients and disaccommodation factors, COZY is easy to use and makes a measurement in 10 to 20 seconds. Also, the calibration of the bridge unit's capacitance and conductance standards can be checked automatically. Though developed primarily for ferromagnetic component work, COZY is a general-purpose bridge; it measures inductance, capacitance, resistance, and conductance over wide impedance ranges at frequencies between 200 Hz and 30 MHz. This paper describes COZY'S hardware, software, and performance.