Various type of dimmer circuit is already available online, and the idea of lamp dimmer is not new to electronics hobbyist. This light dimmer is very efficient because no power is dissipated in the resistive elements. In SCR light dimmers the firing angle is controlled as a result of which the waveform is distorted. But it is not so with this circuit. The load in this case always works with sine wave irrespective of power delivered to the load or the type of load. The brightness of the lamp can be controlled in many steps. Two lamps, each of 25W, can be operated together. If wattage of the load is more, the capacitors need slightly adjustments. Using suitable value of capacitors any type of load can be controlled. Further, the load is protected from transient.
Circuit Description of Lamp Dimmer
C1, C2, and C3 are so chosen, so as to given ¼, ½ and 3/2 of the total power to the load. The capacitor c4 – C7 absorb transient voltage and protect the lamp.
Unlike SCR lamp dimmer, this circuit does-not need any triggering circuit. If needed, fuse of suitable rating can be included in the circuit.
PARTS LIST OF LIGHT DIMMER CIRCUIT
R1 = 200KΩ/2W
C1 = 2 µF/400V, AC
C2 = 3.3 µF/400V, AC
C3 = 4.7 µF/400V, AC
C4 – C7 = 0.1 µF/400V, AC
SW1 = DPDT Switch On-Off
SW2 = 1-Pole 4-Wat Switch