Filament Light Dimmer Circuit
This simple triac dimmer can be used to control incandescent filament lamps up to 200W. The circuit operates on the phase-control principle.
PARTS LIST | |
R1 | 10kΩ 0.5W |
R2 | 100Ω 0.5W |
VR1 | 500kΩ Potentiometer |
C1 | 330n (0.33µF) |
C2 | 100n (0.1µF) |
D1 | DB3 Diac |
Q1 | BT136 Triac |
L1 | Filament Light |
The main control is provided by VR1. This determines the rate at which C1 charges and hence the point along the mains waveform at which the voltage on C2 reaches the breakdown voltage of the diac (D1), which is when the triac is triggered.
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BT136 Triac pin configuration | DB3 Diac |
Interference suppression is provided by R2 and C2.
This light dimmer is directly connected to mains. So be careful.
The potentiometer should have a plastic spindle.
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