| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To avoid control malfunction near a lower dimming limit and to secure a proper dimming control range without considering a type of a load, the number of connection or variation of components in advance. <P>SOLUTION: This dimmer is provided with a control circuit 21 wherein a closed circuit is constituted by connecting a bidirectional switching element Q1 having a self-hold function, a lighting load 4, an AC power supply 1 in series, and which performs phase control of the bidirectional switching element Q1. The control circuit 21 is a DC trigger type phase control circuit which continues giving a drive voltage while the bidirectional switching element Q1 is on, which has a means (current transformer CT, etc.) for detecting the commutation of a current flowing in the closed circuit to control an ignition phase angle of the bidirectional switching element Q1 based on the time of commutation of the detected current. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
