Transistorised transmitter amplifier circuit - has control circuit to adjust driving point of DC voltage to avoid collector-base barrier layer breakdown and transistor failure

摘要

Common emitter type transistorised transmitter amplifier arrangement is designed to avoid transistor damage as a result of break-through of the collector-base barrier layer, commensurate with the lowest possible design costs. To meet the safety requirements, a control circuit is provided to adjust the driving d.c. voltage (Uo) when, as a criterion for bringing in regulation, a threshold value is reached by the base-emitter voltage, at which the latter voltage changes in the positive direction as a result of breakdown of the collector-base barrier layer.