High-speed electromechanical digital voltmeter

Conclusions

A method for raising the operating speed of dc digital voltmeters using contact elements is suggested and a schematic for a high-speed digital voltmeter supplied.

The peculiarities of the above instrument consist of combining the relaxation relays (dc amplitude analyzers) with the compensating part of the voltmeter and in a special circuit for eliminating the possibility of an incorrect operation of a relay.

If the required elements are added to the above circuit it is possible to make a multirange voltmeter with an automatic inducation of the polarity of the measured voltage. Difficulties may arise in adjusting the relaxation relays to low voltage operating levels. In this case the circuit may be supplemented by an additional amplifier with a gain of 10, and a negative feedback large enough to make the total effect of the zero drift and gain instability smaller than the minimum calibration of the instrument.