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What resistor is needed to make enough heat from a PP3 9V Battery to pop a ballon?

dixie48

Sep 15, 2010
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What size resisor would i need to generate enoughheat from a pp3 9 Volt Battery to pop a Ballon
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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determine the short-circuit current from the battery and then pick a resistor that will draw about half of that current across the battery voltage.

Then get the smallest size resistor you can of this value (probably a surface mount type).

As long as the power isn't applied long enough to make it smoke, you should get enough heat to pop the balloon.
 
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Resqueline

Jul 31, 2009
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The procedure suggested by steve will give you the fastest possible pop (possibly around a tenth of a second?). R = 4.5V / Isc.

I don't know what temperature it takes to pop a balloon, but here are some practical values of approximately what to expect from an 1/8W (0,125W) resistor in free air.:

150 ohms = 60mA = 0.5W = 90 degrees C.
82 ohms = 110mA = 1W = 150 degrees C.
56 ohms = 150mA = 1.4W = 200 degrees C.

I'd suggest to try using an easily manageable 47 ohm 1/8W resistor, which will yield a considerable temperature but which still won't go up in smoke.
 
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THUNDERBOLT

Aug 29, 2010
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How did you get 150°C and the other values please??

That would be handy to know, I just don't know how to do that calculation. Thanks
 

Resqueline

Jul 31, 2009
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I didn't calculate the temperatures, I measured them with a thermal image camera. I didn't calibrate it though so please consider the values as being approximate.
Many resistor datasheets will present a surface temperature at the rated power. The other values (resistance, current, power) are from Ohms law. See Tutorials above.
 
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