| 摘要 |
PURPOSE:To enable sure assignment of H- and L levels in the stage of starting welding and to prevent welding defect by setting a flip-flop circuit in the stage of starting the welding and resetting a counter so that the clocking is started from 0. CONSTITUTION:In the case of an L start, a switch is shifted to a contact L, and a terminal is dropped temporarily to a ground level in the stage of starting the welding, by which a flip-flop circuit 90 is reset to Q=L, Q'=H, and an NAND gate 88 is reset. A light emitting diode is then lighted and a resistance is selected so that the welding voltage is set at a low voltage. The one input terminal of the gate 92 is dropped to the ground through a diode 106 to produce the output of an H level. Counters 62, 64 are thus reset and the clocking is started from the welding start. Since the gate 88 opens, the period L1 when a switch group 70 outputs is selected and the first inversion of the flip-flop 90 takes place after the lapse of the period L1. |
