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Anonymous
Anonymous asked in Science & MathematicsEngineering · 1 decade ago

Heating element troubles?

I'm trying to make a small heating element from some heating coil (made from nichrome wire) from a hair dryer. I'm using about 2 inches of it with a 9 volt battery but what keeps happening is that the coil will initially heat up, but then the battery will start to heat up and the coil will start to cool down. I would like to know what I am doing wrong plus any advice anyone can give me about heating elements. Thanks.

Update:

(Response to first answer:) But if I try a longer wire, won't there be less heat? I'm trying to get about enough heat to melt a marshmallow.

Update 2:

Also, could the problem of the battery's power lowering over time be solved with a joule thief?

Is the heat produced determined by the voltage or current?

Update 3:

A joule thief is a circuit (thingy) that can increase a battery's voltage to a desired level (the battery does die faster, though). Example: you could use a 1.5 volt battery to light a 3 volt LED.

http://www.evilmadscientist.com/article.php/joulet...

2 Answers

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  • 1 decade ago
    Favorite Answer

    EVERYTHING that is happening is because of excessive current. And if you are using a little 9V transistor battery, it is incapable of sustaining the type of current you are expecting it to, thus the increase in internal resistance, reduced voltage, and dropoff in current. The battery overheats.

    Joule thief? What's that?

    Doesn't matter, you are trying the impossible with what you are doing.

    You might do better with a low voltage battery of large size, but a couple of inches of Nichrome will still have a very low resistance, and will either burn up, or produce the same overcurrent result.

    Lower voltage (like 1 1/2 volts) and a longer piece of wire might work to some extent.

    Source(s): Ohm's Law.
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  • goober
    Lv 7
    1 decade ago

    There is too much load on the battery. The internal resistance of the battery causes heat dissipation in the battery which increases its internal resistance and that reduces the power to the heater.

    Try a longer wire.

    A 9v battery is not a good power source for a heater if you are looking for more than just a tiny bit of heat. It does not have a lot of stored energy.

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