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Need help with a circuit again

Posted: Mon Mar 26, 2018 3:53 pm
by 1moldmaker
I was wondering if there was a way to add a sensitive gate triac to this Schmitt trigger circuit. D2 is normally on. Press S1 and D2 turns off and D1 turns on and stays on for two seconds after switch is released. What I would like it do is instead of turning on and off an led, is turning on and off a 12 vac relay or a 12 vac light, and possibly making this a spdt solid state relay for low voltage ac 10-20vac.
thanks

Re: Need help with a circuit again

Posted: Tue Mar 27, 2018 5:23 am
by sghioto
Easiest solution is to use a solid state relay or what they call an opto-triac. Depending on the current required a MOC3020 may be adequate.
SG

Re: Need help with a circuit again

Posted: Tue Mar 27, 2018 6:45 am
by 1moldmaker
I will be pulling some amperage, up to 10 amps max,
Would I put the optocoupler where the leds would go?

Re: Need help with a circuit again

Posted: Tue Mar 27, 2018 5:39 pm
by 1moldmaker
One other thing, I was wondering if I could put the gate of the triac with the 1k resistor instead of the led, would that trigger the triac?

Re: Need help with a circuit again

Posted: Wed Mar 28, 2018 7:54 am
by dacflyer
you can get SSL as high as 100 amps or more...
i got a bunch that are good for 25 amps. i think the input is 24 volt range,, i'd have to look..,

Re: Need help with a circuit again

Posted: Wed Mar 28, 2018 8:21 am
by 1moldmaker
What is an SSL?

Re: Need help with a circuit again

Posted: Wed Mar 28, 2018 6:51 pm
by sghioto
One other thing, I was wondering if I could put the gate of the triac with the 1k resistor instead of the led, would that trigger the triac
Not in this case as the triac will be on continuous. Best solution is to use an opto-isolator.
For 10 amp loads you can use the MOC3020 to drive a high current triac such as BTA16 rated at 16 amps.
SG

Re: Need help with a circuit again

Posted: Thu Mar 29, 2018 5:49 am
by 1moldmaker
Thanks again, that's is exactly what I was looking for,

Re: Need help with a circuit again

Posted: Thu Mar 29, 2018 12:21 pm
by haklesup
SSL?, I think he means SSR, Solid State Relay. Lots on Digikey but 12V ones were expensive. The nice part about an opto-isolator is that the switching and load supplies can be completely separate.

Re: Need help with a circuit again

Posted: Mon Apr 02, 2018 12:34 pm
by dacflyer
1moldmaker >>> solid state relay

check out CRYDOM solid state relays...they got all kinds..