Thread: How to match "wall warts" with electric motors?

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Originally Posted by Xane

Also, don't forget you don't need to match the exact voltage, you just need to be exact or higher. If you have a higher voltage, you can pull it back down with resistors.

Are you talking about the adapter being higher voltage than the motor? Shouldn't it be just the opposite?

Hmm? You need the adapter to be the same or higher than the rating listed on the item you want to power. If you have a motor that needs 9v but can only find a 12v wall wart, then you'd use a resistor calculator to find out what resistor to use to bring it back to 9v. You need to know the amperage needed by the motor as well. As long as the amps are equivalent to or higher than what the power needed is, higher voltage is fine. If you have a 6v wall wart a motor will either run slower or not at all, and the wall wart may overheat and break.

You can even bring 12v down to run a 3v item but you'll need a high wattage resistor and be wasting a lot of power.