| 摘要 |
PURPOSE:To reduce the entire circuit of a circuit and the leakage current and to improve noise resistance by providing a zero crossing circuit in a control circuit of a thyristor energized by an induction load, and connecting a capacitor in parallel with both ends of the thyristor. CONSTITUTION:In a circuit in which an induction load 11 and a thyristor 13 are connected in series with an AC power source 12, a capacitor 16 is connected in parallel with both ends of the thyristor 13. A zero crossing circuit 14 is provided in a control circuit for applying a gate pulse to the thyristor 13, and a turn ON or OFF signal is supplied to the gate of the thyristor 13 with the zero crossing voltage immediately after a control signal is input to control input terminals 15, 15'. Thus, since a rush current is not flowed to the thyristor 13, it can be protected, and since the capacity of the capacitor 16 can be reduced, the size can be reduced, and the leakage current can be reduced. |
