| 摘要 |
PURPOSE:To reduce the malfuction of a circuit, which transfers signals while maintaining electrical insulation, due to a noise by widening a blind sector against a noise, by providing either shunt or voltage divider circuit to the luminous element of a photocoupler. CONSTITUTION:In the circuit which transfers ON-OFF signals of a contact, etc., resistance RD is connected in parallel to diode LED so as to shunt current IR flowing to diode LED to resistance RD by using the photocoupler equipped with light-emission diode LED and photo transistor PT. Then, it is made possible to discriminate that the contact turns ON when the current flows to diode LED a half as much as ID, thereby widening the range in which the mixing of a noise can be discriminated. It is also recommended to connecting Zener diode ZD in series to the circuit obtained by connecting diode LED and resistance RD in parallel, and the voltage is divided at the same time so as to widen the range of a blind sector, thereby widening the margin against noises. |
