Looking for simple Triac circuit

good starting point for loadsa stuff

martin

This application is specific, so the load will always be a couple hundred watts on the master and the other loads.

Any idea where that simple circuit may be found on the net?

Ted

You think that " several transistors, diodes, etc. " = complex ????

I suggest you re-think.

Esp for a master slave configuration.

Graham

"ted weber"

** Those "really simple" circuits usually had a serious flaw.

When low current loads were used as the master, the triac was not reliably triggered in both polarities resulting in a DC component reaching the other loads - then the smoke got out.

.......... Phil

Try

Just a current transformer over one leg of the master power line, feeding the gate of a triac, said triac switching the slave.

John

then

several

There are always unstated details, it seems.

Well then, you could rectify and filter the gate drive, or have the ct drive a small rectifier/filter into a power ssr.

John

then

several

Maybe unlikely, depending on the nature of the loads, but I'd be a bit worried about possible asymmetrical triggering, leading to DC in the winding of a transformer or motor which might be in the switched load, and thus copious amounts of smoke pouring out and that sort of embarassing outcome.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

On Sun, 23 Oct 2005 10:37:44 -0700, John Larkin wroth:

That's a good solution for resistive loads, but if the master is some sort of partially inductive load with the current lagging the applied voltage, then the slave may see a somewhat chopped version of the AC line voltage. At least on the first half cycle. That may or may not be a problem.

The four-quadrant gate action may take care of keeping the triac turned on for half-cycles after the first.

Jim

You might be thinking of a circuit like the one at

It's not very complicated, as power control circuits go. If you absolutely want a triac to control the slave loads, just replace the relay with am optoisolator and triac combination. You can also replace the homemade current sensor with a real current transformer that will be more predictable.

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in 
the address)

Never take a laxative and a sleeping pill at the same time!!

"Ross Herbert"

** ROTFL !!!

That is EXACTLY the sort of schematic the OP was complaining about.

Chocka with complication !!!

.......... Phil

Look for "Jim Thompson Inspired Switch" in the abse newsgroup. I'll be posting it today.

Ed

It's the newsgroup, news:alt.binaries.schematics.electronic . You need a real news server at your ISP (or I guess there are news servers for hire out there these days). I notice you're not a google poster, so you probably have it unless your local sysop is censoring you. ;-)

Good Luck! Rich

Thanks very much. Where is abse?

Ted

I posted this a while back, put a MOV across the L and N where they enter your little *plastic* box containing the parts. It uses the Radio Shack 10A relay (1200VA load). If your master load causes triggering problems then you may have add a line rated 0.1U capacitor between its switched line and neutral. View in a fixed-width font such as Courier.

. . . . RS relay 275-217 . . .-------------------o----v . | o-------+-----. . | | | . | 1A ------ | | . | 400V .-|\\ \\ \\ |-. | | . | TRIAC | ------ | | | . +-----||--|>|------+ | | | . | \\ | | | | | . L ---| |--+---|