Transistor Modulators for Low-level Direct Current Signals

Abstract

WE have considered in some detail the problem of using germanium and silicon transistors as choppers in thermocouple-amplifier and other low- and medium-impedance applications. In the past, several circuits have been described using asymmetrical transistors with switching drives which are symmetrical or asymmetrical with respect to the emitter and collector of the transistor. Many of these circuits require careful adjustment and/or selection of transistors to reduce the equivalent input drift with temperature to an acceptable level.