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Hi,
Not really. All they can do is limit the voltage and current going into the coil. The heat is a byproduct of the `transformer action` and all coils will heat up some. If you're giving it too much voltage, a resistor could help to bring the heat level down to an acceptable level if it's running too hot.
If you're using DC for your magnetic coil, take the available voltage, then subtract the operating voltage of the coil and divide that by the current of the coil, which will then give you the value of the resistor you need. Example: 12 volts (available) - minus coil voltage, divided by the coil's current in milliamps (or amps), which equals the value of resistor in ohms.
As for the power rating of the resistor (in watts) just multiply the available voltage times the current of the coil, giving you a rating in watts, and then pick a resistor with at least that much power handling capability or go a size larger if you wish. (This isn't the exact formula, but it's close enough to take care of your needs, I think.)
Hope this helps,
Cubby
Wiki User
∙ 16y ago
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