| 摘要 |
PURPOSE:To eliminate signal line between units by connecting a switch between a second negative power supply line and the cathode of a constant voltage diode connected between a first negative power supply line and one of two units while furthermore connecting a photocoupler between the second negative power supply line for the other unit and the anode of the diode. CONSTITUTION:Upon turn ON of a switch S under a state where units A and B are operating independently, current in a circuit system 1 is fed back from the switch SW to the minus power supply side of a circuit system 1 through a load resistor R1, minus power supply line of a circuit system 2, and a LED in a photocoupler PC. The LED in the photocoupler PC on the unit A side is lighted by the current flowing through such bypass loop and thereby a transistor in the photocoupler is turned ON to produce an output voltage Vout. Consequently, signal can be received by detecting the output voltage Vout at the unit A. According to the constitution, signal lines between the units A and B can be eliminated. |
