What should i do?

I’m working on an electro magnet for a science fair project. I was wondering if I should just add a small resistor to each terminal of the battery pack so the batteries don’t overheat. Any other ideas on what I should do.

1 Answer

  • Jon W
    Lv 5
    1 decade ago
    Favorite Answer


    Yes, build a DC power supply for extra credit and you won't have to worry about the batteries.(although, given Murphy's law, I'd have the batteries ready to snap in at a moment's notice.

    Just need a transformer, diodes or a SCR, a capacitor and a A/C line cord off of something that's broken.

    You need to know maximum milliamps that your batteries can safely put out. Look it up on manufacture web site.

    Measure the resitance in your magnet. Measure your battery voltage or voltages if they're in series.

    In series you're only going to get what the weakest one can handle.

    Use Ohm's law to figure it out out the current.

    If the batteries are wired in parallel, you can pull the maximum amperage from them.

    If this would cause the batteries to go above their maximum ratings you could put in a resistor, or a potentiometer if you have one that'll take the power.

    With a "pot" you can adjust the power when you're not showing it to anyone and it doesn't just waste power like a resistor would. Might end up with a combo...

    I recommend NiMH rechareable battery as they're designed for high drain.

    Oh yeah. See what the max. allowed temp for your batteries are also.

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