| 摘要 |
PURPOSE:To improve the easiness of maintenance, etc. CONSTITUTION:Since electrostatic capacity to determine the time constant of an active unit 1 is determined by only a capacitor 4, and in a spare unit 11, it is determined by the sum of the capacitors 14, 15, the time constant of the active unit 1 is shorter, and since a reset circuit 3 stops outputting a reset signal earlier than the reset circuit 13, the output of a NAND gate 2 becomes '0', and the active unit 1 starts up first. Besides, the output of the NAND gate 2 is inputted to the input terminal 18 of the NAND gate 12 through an input/output terminal, and the output of the same NAND gate 12 is kept at '1', and the spare unit 11 stands by. On the other hand, when the active unit 1 is disconnected while the active unit 1 is working, the input terminal 18 of the NAND gate 12 is made '1' by a pull-up resistor 20, and the output of the NAND gate 12 becomes '0', and the spare unit starts up. |
