Telephone electroacoustic transducer modulator amplifier - has symmetrical transistor bridge and maintains total constant current

摘要

The amplifier consists of a symmetric bridge and is intended for modulating an electroacoustic, electromagtic, electrodynamic transducer (1) in a subscriber's telephone set. The bridge has four linear components and a device (8) to maintain the total current passing into the amplifier constant. The bridge's components comprise transistors (21, 31, 41, 51) connected to pilot circuits (22-25, 42-45). These circuits contain current inverters (22, 23, 42, 43).