DIY SSR (Solid State Relay) ??? Can I ???
Whats inside a Solid State Relay? I bought 4 off ebay but daum, there not cheap.
I want to use Logic Level TTL or 5v (From a Pic(axe) ) whatever you want to call it, to switch 110v ac mains power to lights, like in a Christmas light show.
Suggestions?
Thanks-
Andrew
-----------------------------------------------------------------
Please bear with me, I am still new to electronics! Thanks!
-----------------------------------------------------------------
http://rogertango.com/searchplugins/
Octopart and Digikey search plugins for Firefox
(Accepting suggestions for other sites to be coded)
Well, I did find this info-
Solid state relay - Wikipedia, the free encyclopedia
Feedback on the data from there?
Id be interested to know WHICH MOSFET and OptoIsolator I would want to use to build my own please.
I figure no more than 100w of 110vac power across the "relay legs".
Thanks so much!
Andrew
-----------------------------------------------------------------
Please bear with me, I am still new to electronics! Thanks!
-----------------------------------------------------------------
http://rogertango.com/searchplugins/
Octopart and Digikey search plugins for Firefox
(Accepting suggestions for other sites to be coded)
Well a AC solid state relay is a opto-isolator driving a triac device. Attached is a typical schematic of what is involved at the internal component level. Note sure if you could build one cheaper.Originally Posted by RogerTango
http://www.discovercircuits.com/PDF-FILES/lowssr2.pdf
Your best best is to keep checking E-bay for surplus bargains and pounce when you see a good deal, even if you don't have an immediate need. The larger ones (the 2" square ones) are pricey because they are rated to handle up to 20 or more amps circuits on their outputs which is a lot of current to switch on and off. What the manufactures don't always make real clear is that those square one require quite a large heat sink to actually be able to handle their maximum rated current.
Lefty
Last edited by Leftyretro; 21st December 2008 at 04:53 AM.
Measurement changes behavior
Relays are easy to get and cheap. SSR's can be costly and need heatsinks.
There are lots of choices for 1-2A solid state relays. They are made by Toshiba, Crydom, etc. and are sold for $4 and up at distributors like Digikey and Mouser. They are PC board mount and don't have handy screw terminals, which might be a pain. Use the Part Search to find them. News: I just noticed All Electronics has one! CAT# SRLY-19 is a 1A solid state relay for US$3.25. There are others, such as SRLY-20 which is a pricey $6.50 for 3A.
Don't let the David Johnson PhD circuit scare you! His circuit is special because it needs only 50 microamps. Ordinary SSRs use about 10 mA and replace everything to the right of Q1 with just an MOC3020 (6 pin DIP) or a close relative. But it's still no fun building a solid state relay when you know how to get one in your price range.
Another option: If you aren't dimming anything, have you considered small relays?
Thanks all, I too have found that All Electronics has the 1a SSR for about USD $4, thats cheap enough to buy a dozen or so for the stock shelf!
I think for the effort needed, and the cost of all the parts, it would just be cheaper and easier to get the ones that All has.
But, I did at least learn something about SSRs!!
Thanks for the info everyone,
Andrew
-----------------------------------------------------------------
Please bear with me, I am still new to electronics! Thanks!
-----------------------------------------------------------------
http://rogertango.com/searchplugins/
Octopart and Digikey search plugins for Firefox
(Accepting suggestions for other sites to be coded)
Hi, all...first post.
Since you are planning a computerized Christmas display, I suggest you go to Do It Yourself Christmas and check out their SSR's. They are specifically designed to do just that. While there, you can look at some of the other boards, that make implementation easy.
Here's a link to what I think is one of the BEST Christmas light displays. Check out the videos, with sound on...
Holdman Christmas Lights
I am currently building two DIO96 boards, for 192 channels. I have about 70 relays I've bought off ebay, and I'm going to be building the rest. I'm even thinking about another 96 board, for 288 channels...I like lights!!
Good luck, it's great when you get it done!!
Roger
Reply With Quote
