| 摘要 |
PURPOSE:To improve safety by supplying electric current into a control electronic apparatus in a system only when a key switch and an operation controlling switch which are installed into a power circuit are turned ON, and cutting- off said electric current only by the circuit opening instruction for the electronic circuit. CONSTITUTION:When a key switch 2 and an operation control switch 3 are closed, transistors 7 and 6 are brought into conduction. Then, a power current is supplied into an electronic control circuit 9 through a stabilizing circuit 8. Since a transistor 10 is in OFF-state and the both transistors 6 and 7 are thyristor- connected at this time, the transistr 7 is supplied with a base current even if one of the both transistors 6 and 7 is turned OFF, so the transistor 7 is not set into OFF state. Only in the case where the key switch 2 is OFF and a side- brake switch 14 is OFF cutting-off the power supply is permitted, for example, the control electronic circuit 9 turns ON the transistor 10, and the transistor 7 is turned OFF. |
