| 摘要 |
PURPOSE:To almost eliminate the fluctuation of an output voltage due to the fluctuation of an input voltage, by constituting a shunt circuit supplying a current to a collector of a compared transistor (TR) and a base of a control TR with a constant current circuit. CONSTITUTION:A voltage difference between an output voltage V0 of a control TR2 and a reference voltage Vz2 of a Zener diode D2 is applied between a base and an emitter of a comparison transistor TR1. The base of a TR2 and the collector of the TR1 are connected and a shunt circuit 5 supplying currents IC1 and IB2 respectively is constituted with a constant current circuit consisting of a TR3, a resistor R1 and a Zener diode D1. An input DC voltage Vi is connected in series with the D1, a resistor R3 and a switch SW, and the connecting point between the D1 and the R3 is connected to the base of the TR3. When the SW is closed, a collector current IA of the TR3 is constant with a Zener diode Vz1 even with fluctuated voltage Vi. Thus, even if the voltage V0 is fluctuatied and also the collector current Ic1 of the TR1 is fluctuated, the fluctuated component is compensated with a base current IB2 of the TR2 to keep the voltage V0 constant. |
