I want my ESP8266 to drive eight relays with 12 VAC coils for my home automation system.

This is not a duplicate of this question because there's an additional catch - I have strict space constraints and I want to use as few additional components as possible. Also the G3VM-61A1 MOSFET SSR comes in a nice, small DIP-4 package.

The specs of the relay (a Finder say that the coil takes 12 VAC and 370 mA; a single GPIO of the ESP8266 can source up to 12 mA at 3.3 V.

The Finder is a step relay, so the ESP8266 will only need a 0.1s pulse to make it toggle - the software will take care that no two GPIOs will be on at the same time.

I'm quite at ease with digital logic, but anything above 5V or involving AC always make me think that I'm overlooking something. I know I don't need a flyback diode, but maybe a snubber...? Also the maximum load voltage for the G3VM-61A1 is 60 V AC peak, would that be enough?

Will my circuit work at all?


simulate this circuit – Schematic created using CircuitLab


Your circuit is working well. Only the protection diode is left, which must be bidirectional at AC voltage. The type of opto MOS relay is indifferent here. Yours is good too, only I don't have a model for it. opto12


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