Submitted by: KK Hau (olihou@gmail.com).

The traditional dimmers work by phase chopping of AC waveform to control the duty cycle of power applied to the incandescent lights, through triggering ON a triac at a phase angle corresponding to a dimming level. However a triac needs a holding current in tens of milliamperes to maintain ON, a condition not often met by LED lights because they draw much less current than the incandescent lamps. Consequently, the dimmer cannot be turned ON as it should when driving the LED lights, resulting in flickering. The proposed project is to develop a wall dimmer with zero or very low holding current so that any small power lights can be dimmed smoothly.