Need help with a circuit again

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
Post Reply
1moldmaker
Posts: 53
Joined: Sat Nov 08, 2014 4:38 pm
Contact:

Need help with a circuit again

Post 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
Attachments
Schmitt Trigger N&V.jpg
Schmitt Trigger N&V.jpg (18.38 KiB) Viewed 5993 times
sghioto
Posts: 326
Joined: Wed Dec 26, 2007 5:16 pm
Location: Colorado
Contact:

Re: Need help with a circuit again

Post 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
1moldmaker
Posts: 53
Joined: Sat Nov 08, 2014 4:38 pm
Contact:

Re: Need help with a circuit again

Post by 1moldmaker »

I will be pulling some amperage, up to 10 amps max,
Would I put the optocoupler where the leds would go?
1moldmaker
Posts: 53
Joined: Sat Nov 08, 2014 4:38 pm
Contact:

Re: Need help with a circuit again

Post 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?
User avatar
dacflyer
Posts: 4773
Joined: Fri Feb 08, 2002 1:01 am
Location: USA / North Carolina / Fayetteville
Contact:

Re: Need help with a circuit again

Post 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..,
1moldmaker
Posts: 53
Joined: Sat Nov 08, 2014 4:38 pm
Contact:

Re: Need help with a circuit again

Post by 1moldmaker »

What is an SSL?
sghioto
Posts: 326
Joined: Wed Dec 26, 2007 5:16 pm
Location: Colorado
Contact:

Re: Need help with a circuit again

Post 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
Attachments
Schmitt Trigger N&V.jpg modified.png
1moldmaker
Posts: 53
Joined: Sat Nov 08, 2014 4:38 pm
Contact:

Re: Need help with a circuit again

Post by 1moldmaker »

Thanks again, that's is exactly what I was looking for,
User avatar
haklesup
Posts: 3144
Joined: Thu Aug 01, 2002 1:01 am
Location: San Jose CA
Contact:

Re: Need help with a circuit again

Post 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.
User avatar
dacflyer
Posts: 4773
Joined: Fri Feb 08, 2002 1:01 am
Location: USA / North Carolina / Fayetteville
Contact:

Re: Need help with a circuit again

Post by dacflyer »

1moldmaker >>> solid state relay

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

Who is online

Users browsing this forum: No registered users and 6 guests