Supersensitive electrical measurements and their associated techniques

Abstract

Low-level electrical measurements have undergone a technological revolution. The paper discusses the new instruments that can measure currents and voltages which are only slightly larger than the theoretical limit of sensitivity. The measurements of such feeble quantities are naturally highly vulnerable to extraneous effects, but the strenuous efforts required in dealing with them are richly rewarded with the pedagogic and heuristic benefits derivable. Accordingly such measurements should be included in an undergraduate curriculum.