An Automatic Resistance Thermometer Bridge
Robert D. Cutkosky · IEEE Transactions on Instrumentation and Measurement · 1980
A microprocessor-controlled bridge is described that utilizes a 15-Hz or 30-Hz square waves to excite a shielded multistage transformer. Transformer taps are relay selected to null the detector. The reading, up to 32 Ωin steps of 1 μΩ,is then displayed. An IEEE-488 bus provides remote operation.