Amplification circuit with improved linearity.

摘要

An amplification circuit comprising a differential amplifier is disclosed. An npn transistor (20) composing the differential amplifier having its base provided with negative feed back, the base potential is brought to a constant potential, i.e. a virtual ground potential. The voltage between the base and emitter of the transistor (20) is thus kept constant, and the internal resistance of the emitter does not change in accordance with the change of the emitter current. As a result, since the transistor (20) responds only to an input signal current converted by a resistor (23) and operates, the linearity between the input and the output of the differential amplifier is improved.