| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light control device in which occurrence of flickering of brightness due to an ignition failure of a thyristor at a light loading is prevented. <P>SOLUTION: The light control device has a first phase control circuit PC 1 provided with self arc-extinguishing type control elements Q1, Q2, and a second phase control circuit PC2 provided with the thyristors T1, T2. Furthermore, this is equipped with a control means CC which is constituted so that the self arc-extinguishing type control elements Q1, Q2 of the first phase control circuit PC1 are actuated by a gradient control at a desired phase of an AC voltage half wave, and next, when its conduction reaches a nearly saturated state, so that a short time trigger signal which continues for an ignition required time and discontinues only after a reset time is ensured before the AC voltage half wave is finished is supplied to the thyristors T1, T2 of the second phase control circuit PC2, and so that the self arc-extinguishing type control elements Q1, Q2 are turned on. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
