| 摘要 |
PURPOSE:To obtain a stable output by using a circuit having a time constant so as to charge a capacitor connected to an inverting input and setting the potential to a value higher than that at a non-inverting input thereby preventing potential fluctuation of an unnecessary output point at the start of operation of a differential amplifier circuit. CONSTITUTION:Since a capacitor C2 is connected between a common and a midpoint between resistors R4, R6, a base potential of a TR 4 is lower than a base potential of a TR 3 for a prescribed time after application of power, current flows to the TR 3 and then a current flows to a TR 6. A base of a PNP transistor (TR) 5 whose emitter is connected to the power is connected to a base of the TR 6, a collector of the TR 5 is connected to a point C of the inverting input of a differential amplifier circuit, the capacitor C3 is charged via a resistor R8 at a prescribed time after application of power and a potential is increased more than the potential at a point F of the non-inverting input of the differential amplifier circuit. The zero potential is kept to an output point G at application of power, the inverting input is discharged via the resistor R9, equip-potential to the non-inverting input and stabilized, and the output point reaches a steady-state potential at that point of time.
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