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Inductive Load Triac Design

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Check out great circuits to triac control inductive loads like Antique Radio Transformer Supplies

Cheap Variac & Power Switch Schematic Circuits

proven design

What does ABOVE low cost triac turn on circuit mean?

You can turn on any AC item above by only providing a +5 volt DC at 7 ma maximum to opto isolators pin 1 and ground return pin 2. This will turn on/off any 120 vac powered item like a radio, television, charger, lamp, soldering iron, even a refrigerator with an AC motor or drill press because it turns it on/off all the way.

The limit is 600 watts which is the limit of the triac. If you want to use, for larger load, a larger power triac/fuse must be used. Both are readily available. Largest antique radio draw, I have ever seen, was about 200 watts and this triac handles 600 !

With this simple, cheap, real production proven circuit, you can design without a high power mechanical on/off switch. Power switches fail all the time (or just leave items "power switch" on all the time, so no surge arc in its points, and use this triac circuit to turn item on/off externally).

It is easy, with this circuit, to turn on/off a large AC item (any AC powered circuit design) remotely or with a microprocessor, even a very small cheap switch, since your design only has to provide it a 5 volt at 7 ma, zero surge, maximum source.

Circuit also works for 220/440 vac and even 400 cps not just 120 vac 60 cps. This means good for other countries and even large aircraft AC control circuits. You must reduce current to maintain 600 watts or select a triac with higher voltage rating and higher currents for higher power uses. Triac's used above 600 watts will likely also need small cheap heat sink and or if used in high heat environment like desert or direct sunlight or other heat source of ambient air. This circuit OK to 600 watts @ +55C (131F) with no heat sink, cold of course no problem.

What does BELOW low cost triac turn on circuit mean?

Below circuit shows you can purchase a regular on/off and light dimmer control switch gut, at any hardware store, put into a square quad outlet box, with one side also being a dual outlet.

In other words, wiring up dimmer gut to 1/2 and plugging radio into outlets on other 1/2 wired to this same dimmer. Outlets in box are controlled, by this light dimmer, in same quad outlet box. You then can plug in any antique radio and ramp up the power to it and even run at reduced power levels.

This means no radio turn on power surge! You also do not have to purchase an expensive variable transformer called a Variac to accomplish this ! This will make the radios parts like switches/tubes etc. last many years longer !

All parts at retail should be less than $25 USD !

The box, hardware stores now have plastic ones (insulated not iron) that go into walls, behind the wall plates, can now set on floor/anywhere with AC cord coming out, to plug into a wall outlet. Your radio plugs into one of the dual outlets sockets in this external box.

I like to put a plastic wall plate, that matches dimmer hole and outlets holes on top of the box, to protect from anything getting inside and shorting it out.

In other words, it looks like, and is an external quad type wall outlet wired, for external use

Since you can dim external lamps, like work lights, or even solder iron heat, with it, you will not believe how handy this home made, outlet dimmer box, extension cord can be.

WARNING, if item to be plugged in has an AC motor though, ramping up to reduce motor speed will cause motor to overheat, loose power and likely burn up !!!

Do not plug in AC motor item unless dimmer is turned all the way up, or for short time periods only, like 60 seconds !

This circuit below is talking about this inductive motor load problem, whereas now there are expensive control circuits for sale, that will allow speed control of AC motors.

So if you want electronic AC motor speed control, check on your power requirements (watts required by motor under full load condition), then purchase one of these new circuit controllers, now available at hardware stores, but be prepared for a higher price

Inductive load design

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