Low-Amp SSR

[dirknerkle]

Just an experiment so far, but because a single-channel prototype worked fine I thought I'd go the next step and build an 8-channel low-amp A/C ssr. This is a takeoff on Ernie Horning's use of the MOC3023 to control lights directly, eliminating the triacs completely since the MOC alone can apparently handle up to 1A. Obviously it's less expensive and quicker to build. Size: 3.75" x 2"

One sacrifice I had to make was running the A/C power trace beneath the optos. Hated to do that but realistically couldn't come up with another way to do it conveniently on a single-sided board. I reasoned that my plan is to use these with one string of LEDs per channel, so there won't be much current on the board at all and it'll probably work okay. Still, I hated to do it that way because it's a bad idea... I built one and if it tests out, I'll cover the hot traces with either liquid tape or hot glue for more safety and isolation from potential moisture.

I etched 3 boards -- the right two still have the toner on them while the left one is cleaned and ready to assemble. Also shown -- the completed prototype.

[David_AVD]

If running tracks under the optos seems like a bad idea, it probably is.

[dirknerkle]

If running tracks under the optos seems like a bad idea, it probably is.

I couldn't agree with you more, David! Sometimes with a single-sided board you run out of options though...

[David_AVD]

Nah, the valid option is don't make it in that case. LOL

[Aurbo99]

hmm, so a single string of LEDS (70 count) rated at .04amps or even a single string of INCANs (70 count) rated at .44 amps will work just fine for this design?

[dirknerkle]

Yep, apparently. I tested it with a string of 100 incans (.39A) and it worked fine, so I'd imagine .44A would work, too. The MOC is rated up to 1A but I'd sure keep it less than half of that for a little headroom... And the string of LEDs was 100-ct. How 'bout that?!?!?!

Oh, and it'd be better to move the tracing from beneath the optos, of course...

[Aurbo99]

Thanks Dirk

This straight off/on or does it work with dimming as well?

99% of my current display runs 1 string or Incans or LEDs per channel, dropping off the Triac would save some bucks on a retrofit.

[dirknerkle]

Works just fine with dimming. In fact, it could conceivably eliminate some of the flickering issues that happen with the bigger triacs.

This was Ernie Horning's idea, by the way -- he's a wizard!!!

[eswets]

are you going to put this in the copper file of the library? I would like to make one to try it. would work good for arches!

[David_AVD]

Nobody else seems concerned by the lack of LV / HV clearance?