On the Alternating Resistance of Transmitter

Abstract

Static and dynamic tests of a microphone transmitter are described. For a transmitter kept quiet, both constant voltage and constant current tests were performed by noting the variation of current or voltage with respect to time and therefore that of static resistance.
For dynamic tests, vibrations were given to the transmitter acoustically from a telephone receiver carrying an alternating current of audible frequency. Moreover, a direct current was send to the transmitter through a high resistance. Continuous and alternating voltages thus appeared across the terminals of the transmitter were measured with D.C. and A.C. potentiometers. Thus, the no load dynamic characteristics are obtained by varying the alternating current through the driving receiver, its frequency or the direct current of the transmitter.