resistor of what capacity is required to glow a 3.5 volt L.E.D to a battery of 12 volt operating at 280 ampere.
- posted
15 years ago
resistor of what capacity is required to glow a 3.5 volt L.E.D to a battery of 12 volt operating at 280 ampere.
A 12.5 milliOhm resistor will drop 3.5 volts at 280 amperes, and a 1000 watt rating would be sufficient. But then the original load will only have
8.5 volts.Seriously, it does not matter what current the battery is supplying (or what it is rated for). What matters is the current rating of the LED. A small 20 mA LED at 3.5 volts will require R= 8.5/0.02 = 425 ohms at 170 mW.
Paul
0.030 ohm/ 30mohm. Happy smoking!
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