(4) Variable AC Power Supply With a Twist:

by Dr.Bill in Circuits > Tools

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(4) Variable AC Power Supply With a Twist:

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One day I needed a 90 volt AC power source for a project I had in mind. I thought about it for a few days thinking of all kinds of things that I had no parts for. Then one day I was in Home Depot looking for PVC pipe for a plumbing job I needed to do in the house. As was my habit, I walked down the electrical isle and spotted the dimmer controls they had and thought maybe I could use a dimmer switch.

As it turns out, I have found that to get the variable voltage part out of it you need to plug in a window fan as a ballast to stabelize the dimmer circuitry. If you plug in some electronic thing and try to lower the voltage you will get wild voltage swings and damage the equipment. A running fan will stabilize the dimmer and you will get accurite voltage measurements.

Dims lights, controls fan speeds, and provides variable voltages. My computer runs cooler on 115v.
In Hawaii, the voltages are often as much as 128 volts so I plug the dimmer into a surge protector, a fan into the dimmer and turn it on low, measure the voltage to 115v, and plug in my computer.
The computer seems to like it because it runs cooler and so doed the computer power supply.

And Parts Is Parts:

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See the photos below for the parts that were used.
Its pretty simple really.

Assembly:

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The knockout can be hit with the claw of a hammer to bend it in and then grabbed with pliers and twisted around to break it off.
The restraining nut has got to be tight so the wires don't get twisted around inside. If they do, there will eventually be a short circuit.

Electric Wireing:

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Follow the photos closely.................

Dimmer & Outlet:

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When the wireing is done tuck as much as you can in the box under the dimmer and the outlet so nothing is between the outlet and dimmer.

Test the outlet to see that it is wired properly by plugging it into the wall and plugging a serge protector into it. If the protected light comes on, its right. If not, re -wire it the right way. It has to be done right.