Microchip Technology Inc

Zero Cross Detect

The ZCD module detects when an AC signal crosses through the ground potential. The ZCD module is useful when monitoring an AC waveform for, but not limited to, the following purposes.

Available Features:

  • Simplified TRIAC control
  • Dimmer phase delayed drive
  • AC period measurement
  • Minimized EMI caused by switching transients
  • Accurate long term time reference
Zero Cross Detect Info Configuration
Tabs / ZCD
Webinars & Training


Title Date Published Size D/L
TB3138 (DS-90003138) — Zero-Cross Detection Module Technical Brief 09/11/13 230 KB PDF


Title Abstract Recording Date Duration
Overview of the Zero Cross Detect (ZCD) The ZCD module is a peripheral within select PIC® Microcontrollers, that can be used to monitor when an A/C signal crosses through a zero cross detect threshold. It is connected to the designated ZCD pin on the device through a current limiting series resistor. 12/01/11
1.5 hours
Using Zero-Cross Detect (ZCD) Peripheral for Triac Firing Triacs are commonly used to chop AC waveforms to control the amount of average power to the intended load. The firing angle delay is the amount of time between the zero-cross of the AC signal and the time that the triac is turned on (T1 and T2 in figure below). To decrease the amount of power that is transferred to the load, the firing angle delay is increased. 12/01/11 1.5 hours