Telephone transmitter amplifier

A telephone transmitter amplifier comprising a microphone means, an operational amplifier means including a differential amplifier, said microphone means being coupled to an input of said differential amplifier, a grounded collector PNP (or NPN) transistor connected to the output terminal of said differential amplifier and a first constant-current circuit means connected to the emitter of said PNP (or NPN) transistor, an output stage amplifier including a grounded emitter NPN (or PNP) transistor circuit having its base directly connected to the output terminal of said operational amplifier, a smoothing circuit means for smoothing a voltage supplied from a telephone line, and a voltage-divider circuit means for dividing the output voltage of said smoothing circuit to establish preset operating points for said operational amplifier and said output stage amplifier, output terminals of said output stage amplifier being connected in common to input terminals of said smoothing circuit means.