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SPDT Solid State Relay

Posted: Wed Apr 09, 2014 3:35 pm
by mpooley
I have been using these cheap SSR's from ebay "SSR-25DA 25AMP 3-32VDC Output 24-380V AC Solid State Module"

http://www.ebay.co.uk/itm/100-White-Sol ... 5af70a789b


But now I need a similar SPDT. I don't even know if they are made? I can't find any.

does anyone know where I might get one please?

On the other hand can anyone see a problem using two of these with a simple logic inverter on one so that one or the other or the relays will always be on?
I'm switching mains BTW

thanks

Mike Pooley

Re: SPDT Solid State Relay

Posted: Wed Apr 09, 2014 11:53 pm
by Pauldf
I don't see an issue with using two of the devices with the inputs in parallel to give you two isolated outputs, as long as the logic is sufficient to drive them.
Running them as a source sink may have one or two issues depending on your circuit design, a not gate may be your friend here.

Re: SPDT Solid State Relay

Posted: Thu Apr 10, 2014 9:43 am
by mpooley
Thanks Paul
I just quickly knocked up this diagram to show you what I meant,
It's very simple. I would use a 7400 series not gate .
do you think this is OK?
https://dl.dropboxusercontent.com/u/72975406/cct.jpg

didn't know how add an an image!

thanks again

Re: SPDT Solid State Relay

Posted: Fri Apr 11, 2014 3:58 pm
by Pauldf
Yeah, something like that will do.
(pedantic alert - a not gate has a circle after the triangle but me knows what you means)

Re: SPDT Solid State Relay

Posted: Sat Apr 12, 2014 11:19 am
by mpooley
i did know that but I only knocked it up quick using paint lol