white led
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kjd
Go make something!
If you can measure the light outputs on the T1, you could subtract the 3.3volts for the LED from that and divide by 25ma to get resistance. Or just use a 1K resistor.
I usually use NCE docoders and on the HO setting, they usually put out 13.2V. I subtract 3.3V for the LED and divide by the current, 20ma for the ones I used.
(13.2V-3.3V)/.020A=495ohm That makes them very bright and is pretty much the limit, you don't want to go any lower. Upping the resistance a little gives more margin for error and is not maxing out the LED. I like to use about 700ohm. It is still plenty bright.
I usually use NCE docoders and on the HO setting, they usually put out 13.2V. I subtract 3.3V for the LED and divide by the current, 20ma for the ones I used.
(13.2V-3.3V)/.020A=495ohm That makes them very bright and is pretty much the limit, you don't want to go any lower. Upping the resistance a little gives more margin for error and is not maxing out the LED. I like to use about 700ohm. It is still plenty bright.
There is a good article on how to use LEDs (and calculate the current-limiting resistor) at http://circuits4tracks.daxack.ca/Tips.html
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