Time-Varying Dimming Circuit

Published:2011/7/29 8:47:00 Author:Robert | Keyword: Time, Varying, Dimming | From:SeekIC

The picture shows the time-varying dimming circuit.As shown, it uses the unijunction transistor (UJT) trigger circuit, whose function is that it could make the lamp's brightness light up gradually and automatically, or light out gradually and automatically (which means the so-called soft starting or soft stopping). This circuit could be used to control street lamp, home lamp, film-playing place, film-playing room and so on, and these cases would be very adequate. This could make people's eyes adapt to the photometric requirements gradually, so that it is good for eye's health.The working principle: when the S3 is connected, the circuit would get power supply. If the S1 is switched to upside, the C1, C2 would be charged. Because the C2's two ports' voltage is advanced than the C1's two ports' voltage, the C1's charging voltage would be increased firstly and the C2 voltage would follow it to be increased. The SCR's conduction angle would be wider and the lamp's two ports' voltage would be increased, so the lamp would be light up gradually.



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