| 摘要 |
PURPOSE:To improve speediness and to easily attain miniaturization and a low cost by constituting a discharge circuit of an inversion circuit consisting of a photodetector and a resistor, and a bipolar transistor. CONSTITUTION:When the light emitting state of a light emitting diode 17 is set by permitting a current to flow on an input terminal 18, a photoelectric current is generated in a photovoltaic element group 11. Simultaneously, a photodiode 15 in the inversion circuit is also operated by being photoirradiated. At this time, the photoelectric current on the resistor 14 flows also on the photodiode 15, and simultaneously, keeps the bipolar transistor(TR)16 at an OFF state. Therefore, the photoelectric current only flows on the inversion circuit, and a MOSFET12 is turned ON by the voltage drop of the resistor 14. Meanwhile, when no current flows on the input terminal 18 and the diode 17 is set at a quenching state, the cutoff state of the diode 15 is generated, and electric charge accumulated in the gate of the FET12 is supplied from the resistor 14 to the base of the TR16, then, the TR16 is set at the ON state and the FET12 is turned OFF. |
