Current-canceling circuit

Claim 1

In a differential stage electrical amplifier having a pair of npn input transistor for receiving first and second input signals at the respective base electrodes thereof, a current canceling circuit coupled to one of said input transistors comprising: a. a third npn transistor having its emitter coupled to the collector of one of said pair of input transistors, b. a first pnp transistor having its base commonly connected to the base of third npn transistor and having its collector coupled to a first energization source, c. a second pnp transistor having a plurality of collectors, one of said collectors connected to the base of said third npn transistor, and having its base connected to the emitter of said first pnp transistor, and having its emitter connected to a second energization source, d. a first set of serially connected diodes connecting said second energization source to the collector of said third npn transistor, e. a second set of serially connected diodes serially connected between said first set of diodes and the emitter of said one input transistor, and f. at least another diode connecting the other of said plurality of collectors of said second pnp transistor to the base of said one input transistor, thereby providing a biased differential stage having a compensated input for canceling input current to the stage.