| 摘要 |
PURPOSE:To reduce the size of a device by monitoring several kinds of electric power breaks by one detector by releasing a relay when one of the 1st, 2nd and 3rd power voltages is broken. CONSTITUTION:A power voltage V1 is divided by resistances R0 and R1 and applied to a point P to be supplied to the base of a transistor (TR)Q0 via a resistance R2. When the TRQ0 turns on, a point C0 is grounded and a current flows from a power voltage source V2 to resistance R3 and R4 to turn on a TRQ1. As the TRQ1 turns on, a current flows from the power source V2 to a power source V3 through the TRQ1 and resistances R5 and R6. When power voltages V1, V2 and V3 are applied, a relay A is held in an operation state. If, however, some power source is turned off, the relay A is released to detect the power break. |
