| 摘要 |
PURPOSE:To obtain an impedance converting circuit whose one input is common to the said circuit with the linearity of an input versus output voltage attained in an excellent way by connecting a bipolar power supply between a field effect transistor (TR) and the common of the circuit and between a constant current and the common of the circuit. CONSTITUTION:One input of the circuit is common, the other input is connected to a non-inverting input of a unipolar power supply operational amplifier Q1 and an inverting input of the amplifier Q1 is connected to the negative polarity of the power supply. The power supply for the amplifier Q1 is suppressed to a constant voltage by a Zener diode D1 and an output voltage of the amplifier Q1 is connected to a gate of a field effect TRQ2 to control a current iz of the diode D1. The constant current source I1 is connected between the connecting point 2 among the diode D1, the inverting input of the amplifier Q1 and the negative power supply and the negative power supply, and a load RL is connected between the connecting point 2 and the common of the circuit. |
