| 摘要 |
PURPOSE:To inhibit control when two or more of plural control item selecting relays operated and lower the price of this control inhibiting circuit by driving ordinary relays by an electronic circuit instead of mercury relays of polarized relay structure in a control inhibiting circuit at multiplex selection. CONSTITUTION:One side of contacts rl1-2-rl1-n of plural control item selecting relays is grounded and another side is connected through resistances of equal resistance value Ro. These connecting points are connected to negative inputting terminal of a comparator 5, and at the same time, connected to a power source through a resistance Rx. Threshold value voltage is inputted to the positive inputting terminal of the comparator 5, and output is inputted to the base of a transistor Tr. The emitter of the transistor Tr is grounded and the collector is connected to the power source through a relay 4. When two or more of plural control item selecting relays operate, voltage of negative inputting terminal of the comparator 5 becomes lower than the threshold value voltage, and output of the comparator 5 is inverted and the relay 4 is operated through the transistor Tr. |
