What can I use for a cheap current limiting circuit

[Epidemic]

I have a project where I would like to limit current to a circuit.

I would Like to be able to control it from between 0+- & 10 amps.

Any suggestions as to what I should use.

[Epidemic]

I was thinking a rheostat might work but I do not even think they sell those things in lowes anymore. Only those solid state dimmer circuits

[shahani]

There is a kind of transformer in which the Primary and Secondary Coils are actually the same. It's center-tapped. The name escapes me but such a transformer can be used as a current limiter and is better than using a rheostat.

Maybe one of the electical engineer peeps will know better.

[Theophylact]

A fuse is even cheaper...

[Epidemic]

Theo,

Arggggggg!!!!


The wire wound one is nice but I believe that would only be a good solution to AC circuit. secondly most of the ones I have found are in the 1 to 2 watt range. A bit low for my application at the moment.

I can not believe that I can not find a dang rheostat and any of the electronic shops, lighting and electric shops or home improvement center. All they have now is these stupid poopie solid state jobbies.

[shahani]

Its kalled an auto-transformer.

See it here:

http://www.toroid.com/standard_trans...ansformers.htm

What exactly you are trying to do?

Elotrokute a kitty?

Slow and easy?

[mad1]

potentiometer(variable resistor).

[Epidemic]

Thanks shahani. Not quite what I had in mind mainly because that is for AC, i need it to be able to work in AC and DC environments.

Mad If you can find me a variable potentiometer(resistor) that can handle 0 to 10 amps I am all game.

I can not believe that there is no source for a rheostat anywhere.

What the hell is this country coming to.

[Bovon]

A rheostat is the only device I can think of that will give linear control from 0 to (max amps needed).

Rheostats are rated in watts, so depending on the voltage that will be used, wattage can be calculated by P = 1(squared) X R, or.. P = E X I

Where P is power in watts
E is volts
I is amperes expressed in current

Using 12 volts as an example.

P = 12 times 10 = 120 watts (minimum rating of needed rheostat)

Rheostat ohms cannot be accurately calculated because it will be in series with the current flow, and the total circuit resistance would be needed...however, total rheostat Resistance is not needed as long as it has enough resistance to reduce current flow to 0. Very few ohms would be needed to do that when using 12 volts.

Radio Shack used to carry a few rheostats, but the demand is low for such items today. Try an Air-conditioning or heating repair shop, both AC and heating systems use rheostats. Automotive supply places might also have some...older cars and trucks used rheostats... (larger 18 wheelers still do).

[Uncle Bob]

Power pack for a model train. www.micromark.com
My $0.02