I've been designing a smart home system for a while and one of its main features is remotely controlling all the lighting.
I'm using a pretty simple design where the main components are an ESP8266 (talking to a home server), an opto-triac MOC3052 and triac BT136. In essence, the switching part is similar to this circuit (borrowed from elsewhere):
I did not include the snubber in the circuit (because I'm not connecting any reactive load) and now I'm wondering whether I should have.
Everything works splendidly, except that especially in one room, the TRIAC seems to shortly self-trigger when some other lights on the same floor are turned on or off, which causes an irritating blink of the light.
My guess is that this is due to long wires between my circuit and the actual light, so enough power gets induced when other lights are toggled nearby, which is a sufficient spike in voltage for the TRIAC to trigger.
Is my guess correct and is this something the snubber will resolve?
Best Answer
Triacs have a dV/dt specification, above which they can self trigger.
Interrupting loads on the same circuit (so lights in adjacent rooms) can easily cause spikes on the supply.
A snubber will go some way to help, it will increase the threshold, but may not be enough. As these spikes are differential mode, a common mode filter may not be enough.