The compact ac light dimmer module with zero-crossing detector described here is ideal for microcontroller-based ac voltage controlling applications and projects.

A PIC controls a triac connected across the supply by monitoring power line zero-crossing. The PIC controls dimming by delaying the time the triac fires, which trims the peaks off of the AC waveform.

This light dimmer control has active timing capacitor reset or AC line zero-crossing synchronization. The 13 additional components are garden variety and cost less than $2. Performance at the low end ...