| 摘要 |
PURPOSE:To attain clamping close to an ideal state by providing a band compensation and negative feedback function on a DC amplifier circuit utilizing two Schottky barrier field effect transistors(FETs) and receiving an input whose DC component is eliminated by the AC coupling circuit via an input buffer circuit. CONSTITUTION:A clamp level is fed through built-in FETs 1, 2 of a DC amplifier circuit 114. Since the FET 1 is a voltage control element controlling on output current Id by a gate-source voltage, it is not required to supply a bias current, then no bias current supply resistor is required. Thus, the input impedance of the FET 1 in case of viewing an input point A is the forward (or reverse) resistance of a junction diode between the gate and source used as the clamp diode itself. In other word, the effect equivalent to the case that an ideal buffer circuit whose input impedance is infinite is used as the output buffer circuit 14 is obtained. |
