Resistor help with a ddriven cree p4 and 17670

dmc888

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Jul 3, 2007
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I just got done boring out my rc-f4 to fit a protected 17670 cell and have it direct driven with no resistor.

Do i need a resistor with a protected cell? I rather not fry the led.

Which one would be a good choice?

The light is brighter now, but gets pretty warm when I used it for ten minutes.

Thanks for any help.
 

Drewfus2101

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Joined
Jul 16, 2007
Messages
341
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http://led.linear1.org/1led.wiz

This is the site I use. I'm not too familiar with a Cree P4, but guessing at:

Source Voltage: 4.2V
Emitter Forward Voltage: 3.8V
Emitter Forward Current: 1000mA
Resistor: 1 ohm, 2W

I've bought a hand full of those from Newark. They are pretty cheap per resistor and have fast shipping. Good website too.
 
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