An A - C Resistance Thermometer Bridge
نویسنده
چکیده
r '-' A 400 Hz bridge des igned spec ifically fo r measurin g the res istances of platinum the rmometers is desc ribed. Wh en used in conjunction with a co nvent ional 25 ohm thermometer, the instrument ca n resolve a resistance change of 2 micro-ohm s or less, or about 20 microdegrees. It is believed to be in error by no more tha n 3 micro-ohms throughout the useful temperature ra nge of a conventional thermometer. The instrument fea tures an automatic phase angle balance, and ex tensive use is made of multi stage transform ers and operational amplifiers.
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