Optocoupler with TRIAC

Other Hardware General Electronics
1

i am planing to replace the fotek 25DA SSR with a MOC3023M and a TRIAC BTA08 to drive the load. A few doubts with the configuration. I've attached a schematic wired to the best of my knowledge, would that that be correct. The optocoupler is driven by an Arduino from pin 2. The load will be a MOT.

Optocoupler.jpg

2

You need a current limiting resistor between pin 1 of the opto and the Arduino output pin. Also there is no load shown, as it stands the circuit would short out the mains.

3

Thanks Mike !

I've noticed that the load is not added, kept it simple for the ease. A little confused about the triac to go with. Would the BTA08 be ok to switch for just 450ms. The data sheet features says "Minimizes Snubber Networks for Protection" so would be ok to avoid the R16 and C6 snubber components ?

4

Would the BTA08 be ok to switch for just 450ms.

Not too sure what you mean by that. In half a second you will get two cycles of mains. You need to either trigger each cycle or keep the gate on for this length of time. If you have no synchronization to the mains then the triac will trigger immediately and go off at the next mains zero crossing after you remove it.

so would be ok to avoid the R16 and C6 snubber components

It depends on your load. If it is resistave like an incandescent lamp then yes, if it is inductive like a motor then no.

5

More like 30 cycles of mains, at 16ms a cycle.

6 
It depends on your load. If it is resistave like an incandescent lamp then yes, if it is inductive like a motor then no.

Thanks Mike that was what i wanted to know.

7

I can't find the c5 0.05uf capacitor online to buy from ebay. Would this be ok as a replacement ? The load is inductive, here a Microwave Oven Transformer.

8

I can't find the c5 0.05uf capacitor online to buy

Not surprising, I have never seen on in 50 years at this game. Yes that cap you linked to will be fine.

9

Thanks Mike, Your the man :slight_smile: