| 摘要 |
<p>PURPOSE:To supply a trigger current of constant value to an input circuit independently of the power supply voltage, by connecting a constant current element in series with a light emitting diode, which constant current element supplys a driving current of constant value independently of the voltage value of a power supply which applies a driving voltage to the input circuit. CONSTITUTION:When a control signal (e) is delivered to an input circuit 7, a conduction state is obtained and the driving voltage of a power supply 12 is supplied to an input circuit 7. A constant current flows in a light emitting element 2 through a constant current element 22, and the light emitting element 3 generates light. Said light is received by a photo detector 3, and a signal is outputted from an output circuit 8. Hence a photo coupler wherein the limitation caused by the input power supply voltage value is very little and general- purpose properties are high can be realized, by applying the input circuit 7 having constant current characteristics to a photo coupler. By replacing said circuit with a constant current element, a highly reliable device can be obtained, and structural miniaturization is enabled.</p> |
