New principle for exact DC/AC electrostatic comparators

Abstract

A. I. Nefed'ev and S. A. Kravchenko UDC 531.714.75 A principle is expanded for designing electrostatic voltage comparators to operate at 100 to 1000 V with 0.005-0.001% accuracy in the frequency range from 20 Hz to 100 kHz. The sources of error in the electrostatic comparators are analyzed. According to the recommendations of MI 1935-88 [1], the unit volt of ac current can be reliably transferred in the frequency range 0-100 Hz by a thermoelectric voltage convener only by comparison with a standard comparative convener in the range of voltages up to I000 V and frequencies up to 100 kHz. The principle is the same in all countries. The errors of experimental measurement have also been confn'med by crucial comparisons, carried out repeatedly in accordance with CCE-92-04 [2]. It would seem that the problem has been solved. Considering that a voltage of 1000 V is also the reference point, as it were, for power measurements in the transition to higher voltage ranges and for electrical measurements at frequencies up to 100 kHz, it is very important to use another method, an electrostatic method in particular, to create comparison converters, which ensure reliable transfer of the unit volt of ac current to within 0.001%. The point is that in the frequency range 50-100 kHz neglected processes begin to occur in the auxiliary resistors of the thermoelect_dc conveners and the accuracy of measurement drops sub-stantiaUy [3]. Improving the accuracy of electrostatic voltage comparators (EVCs) by traditional methods is made difficult