Hello,

The attached picture shows a circuit from the Motorola's datasheet for the MOC3021 optocoupler.

In the circuit there are 2 snubber networks, and the description says it's one for the triac and one for the MOC3021. But it seems like they are connected in parallel. From the 'LOAD' to 'HOT' you pass a capacitor and then a resistor.. So why have two snubber? The "0.01uF+39R" seems unnecessary to me.

Thanks for the help!

 

It will work with no snubber in almost all applications.
The 39Ω/10nF snubber might be needed occasionally, especially if you use old (not "snubberless" triacs)

 

Yes.. the plan is to use old regular triacs.. snubberless is hard to find over here.

So, should I keep the 39Ω/10nF snubber, even with the 470Ω/50nF?? btw, I'm changing 50nF to 47nF, and the 39Ω to 60Ω

thanks for the reply