HIGHLY ACCURATE RESISTANCE MEASURING EQUIPMENT

摘要

PURPOSE:To facilitate the adjustment of a circuit by constituting the measuring terminal of a resistance measuring circuit so as to measure a resistance by switching two terminals to two super precise resistances per range with the aid of a relay contact and providing an arithmetic means for calculating the integrated conversion gain of an analog circuit for measuring a resistance value and a zero-point drift at every range. CONSTITUTION:A measuring device is so constituted to measure the resistance value by switching measuring terminals P1 and P2 to two super-precise resistances Rr1 and Rr2 per range with the aid of the relay contacts St1-St6 and SR1-SR4. For measurement the resistances Rr1 and Rr2 and a microcomputer MC 5 are used. It selects the resistances Rr1 and Rr2 in the middle of loading or unloading a laser trimming device, etc., calculates the zero-point of the analog circuit of the measuring device and the conversion gain with the aid of measurement data available from A/D-converting 2 the output of an arithmetic amplifier 1 in either case, the set data of a D/A converter 3 setting a target resistance value and the output state of a comparator 4, corrects and calculates the measured results of unknown resistances RX1-RX3 and decides the measured and resistance values.