Autocompensation Device for Ultralow Temperature Measurements.

摘要

A noise-protected meter for ultralow temperatures with a thermoresistor symmetrically connected to a low-noise preamplifier at the input and with a driftless digital lock-in detector at the output is described. The negative feedback circuit includes a multiplier of the analogue signal and the digital code. This principle of circuit construction is found to allow a considerable reduction of experimental errors under actual cryogenic conditions. The resistance range being 0.02-200 k omega , the operating model of the device provides + or - 0.5% accuracy of heat supply below 5x10/sup -14/ W. 4 refs.; 4 figs. (Atomindex citation 19:057144)