Electronic switch with differential transistor pair - is fitted with extra base and emitter transistors which are fed from two DC sources

摘要

The electronic switch has a dc voltage source which is switched through to the base of the fourth transistor (4). This transistor is connected between the emitters of the differential transistor pair and an earthed resistor (5). The base of this fourth transistor forms a third input (8) connection in the amplifier module (1). The bases of the differential pair are coupled via fourth and fifth transistors (11, 12) to a second dc voltage source. The input signal is applied to one of the two decoupling circuits connected to the output side of the second dc source.