| 摘要 |
PURPOSE:To sufficiently compensate a forward voltage of a rectifier irrespective of the amplitude of a load current by driving a field effect transistor by the output of an operational amplifier, and connecting a rectifier with the source of the transistor. CONSTITUTION:An operational amplifier l and an FET 2 are so operated as to compensate the forward voltage of a thyristor 3 by a feedback resistor 6. When the thyristor 3 is turned ON, a current flows through a bias power source 4, a diode 5, the FET 2 and the thyristor 3, and this circuit operates as a noninverting amplifier amplification factor 1. In this case, the power source 4 applies a bias voltage so that the FET 2 correctly operates. When the thyristor 3 is turned OFF, a leakage current determined by the resistor 6 merely flows so that an impedance between terminals A and K becomes very large. At this time, Zener diodes 7, 8 prevent the amplifier l from saturating.
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