Resistance-capacitance trigger unidirectional SCR dimming light circuit

Published:2011/5/5 7:33:00 Author:Nicole | Keyword: resistance-capacitance, unidirectional SCR, dimming light | From:SeekIC

The circuit is as shown, it is a trigger unidirectional SCR dimming light circuit which is composed of resistance-capacitance components, 220V AC power supply is changed into DC pulse voltage by VD1~VD4 bridge rectifier, it is added to the anode and cathode of SCR VT. The trigger circuit consists of RP、R and C2, DC pulse voltage charges to capacitance C2 by RP、R, when it is charged to a value, SCR VT turns on, bulb E turns on and shines. When the pulse is added to the anode and cathode of VT is zero passage, VT automatically turns off, the power supply charges to C2 by RP、R, the circuit will repeat above operations. To adjust potentiometer RP, then it can change the charge rate of C2, so it can change the conduction angle of SCR VT, then the current effective value which flows bulb E will change, it can achieve stepless dimming's purpose. The feature of this circuit is low cost, the shortage of it: the voltage between the two poles of bulb will change in relation to temperature and input pressure.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Control_Circuit/Resistance_capacitance_trigger_unidirectional_SCR_dimming_light_circuit.html

Print this Page | Comments | Reading(3)