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I recently came across this circuit and I'm trying to understand it. This is designed to control an AC heater using a T435-600B-TR TRIAC and an MOC3063S optocoupler, connected to an Arduino Uno.

enter image description here

From my understanding, there is a snubber circuit across the Triac, but looks like the control output from the optocoupler is connected to the wrong node, see image below (highlighted in red is the snubber circuit?). Please correct me if I'm wrong.

enter image description here

I've been doing some reading on snubbers, and seems like this is the expected circuit: (from ST's application note about Triacs/snubbers)

enter image description here

Am I in the right path in identifying a bug on the first circuit?

Any help is much appreciated!

EDIT: The actuator is a heater coil.

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That's not a snubber. That's the supply for the opto-TRIAC. There is no snubber in that circuit.

The 47 Ohm resistor and 10 nF capacitor form a low-pass filter to handle fast transition in the voltage which could otherwise cause the opto-TRIAC to misfire. The top 330 Ohm resistor limits the gate current into the main TRIAC.

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