A High-Accuracy Digital Instrument Design for DC Measurements

A high-accuracy self-calibrating digital instrument design has been developed in order to make available the inherent efficiency advantages of conventional digital meters, but without their limitations in accuracy, reliability, or certifiability. The new instrument can extend the advantages of automation to many testing, quality control, and standards laboratories where heretofore only high-quality manually balanced instruments could be used. Automation at this level of accuracy can eliminate serious cost bottlenecks in the testing of precision devices such as Zeners, resistors, A/D and D/A networks and converters, standard cells, regulated power supplies, voltage and current sources, digital and differential voltmeters and potentiometers, and the dc output of many precision transducers. The paper describes a number of applications of this new type of digital instrument and presents samples of the type of automatic test data obtained.