Keying dimmer lamp using two touch-button dimmer, when the touch of one button, the light will be strong to weak, the touch of another button, the light will be from weak to strong.
Circuit shown in Figure 1 ( Click here to download the schematic diagram ), VD1, VD2, C2, C3 capacitor step-down DC power supply formed by the MOS FET, C1 etc. VS triac trigger circuit. DW for the protection diodes to prevent the FET gate breakdown. When you press S1, the R1 to C1 charge up the gate voltage can be increased SCR trigger current, conduction angle becomes larger, the light increases, the time when you press the S2, C1 discharges along the R2, the gate voltage drops , SCR conduction angle becomes smaller, the light dimmed. When the S1, S2 are released, the MOS FET gate-source resistance of a large, C1 will be basically the same at both ends of the voltage, so the conduction angle of SCR will be the same, the light stabilized.
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