| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a load control device capable of preventing surge breakdown of a semiconductor switching element due to a lightning surge.SOLUTION: A load control device 10 includes a main opening/closing section 1 having semiconductor switching elements 17, a control circuit 4, and a protection circuit 5. The protection circuit 5 has a varistor circuit 18 and a diode circuit 8. The varistor circuit 18 has a parallel circuit of a varistor 7 and a first capacitor 6. The diode circuit 8 has a series circuit of a second capacitor 9, a first Zener diode 11, and a second Zener diode 12. An anode of the first Zener diode 11 is connected to an anode of the second Zener diode 12 via the second capacitor 9. The varistor circuit 18 and the diode circuit 8 are connected in parallel to the main opening/closing section 1. The response time for a lightning surge of the diode circuit 8 is shorter than the response time for the lightning surge of the varistor 7.</p> |
