TV AM transistorised amplifier stage - has working point control circuit operating at very low modulation frequencies e.g. below 10 hz

摘要

Amplifier stage, e.g. for TV transmitter, is designed for improved efficiency with power transistor lay-out. The effective threshold base resistance for the transistor as derived from the working-point control circuit is made small compared with the differential input resistance of the base-emitter circuit of the transistor. The working point control circuit is arranged so that it is effective only for very low modulation frequencies, more specif. for video frequencies below approx. 10 Hz.