Just hooked up another MOC3041 to a TRIAC (BT137 this time) and get the same trigger mid cycle behaviour. Hmmm I am assuming that the 14VAC is not the issue. i.e. It does not need something higher like 110-240VAC. I am at a loss. On 5 August 2017 at 17:37, Justin Richards wrote: > Given the confirmation I will now spend the effort removing another > MOC3041 from a PCB and experiment with it. > > Just double checked and the opto is indeed a MOC3041. > > Justin > > On 5 August 2017 at 17:25, wrote: > >> Your understanding is correct about the MOC3041. Are you sure it is a >> MOC3041 and not an opto-triac without zero crossing detector, like an >> MOC3021? >> >> /Ruben >> >> On Sat, 5 Aug 2017 16:56:08 +0800, Justin Richards >> wrote: >> > The MOC3041 zero crossing optocoupler has been connected to a triac as >> per >> > the MOC3041 data sheet. >> > >> > However, it is triggering the triac to coincide with the input pulse t= o >> the >> > opto. See attachment (is 13kB under the allowable attachment size.) >> > >> > My understanding is the input to the opto needs to be driven high then >> only >> > after the AC waveform has crossed thru zero will the gate of the triac >> be >> > triggered The attached trace clearly shows this is NOT the case. >> > >> > I have varied resistor values and swapped A1 and A2 etc to try and get >> the >> > desired results with no success. >> > >> > Anyone got any pointers as to where I maybe going wrong. Are my >> assumption >> > about zero crossing opto's correct. Has anyone wired these up as per >> the >> > data sheet with success. >> > >> > Notes: >> > The source supply is 14VAC from xformer (will eventually be connected = to >> > 240VAC) >> > The load is 150 ohm resistor >> > A ESP8266 is supplying the trigger waveform. >> > A BTA16-600B is the TRIAC >> > The project is attempting to implement "AC on/off control" and not >> "phase >> > trigger control". >> > >> > >> > Justin >> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .