Rookie mod - Brinkmann AAA

Try using no resistor at all... The mn21/23 has high internal resistance.

This is my first attempt at real mod after being a student of this forum for a few months. Used a Brinkmann 1AAA flashlight. Slightly reamed the reflector to fit a Radio Shack, Blue 2600 MCD intensity, T-1-3/4 5mm LED [Wavelength: 468 nm (typ.), If mA: 20 (max.), Vf: 3.7 (volts typ.), Vf: 4.5 (volts max.)] – which I directly inserted into the existing bulb holder. Assembled / soldered a spring spacer, plastic wall anchor, bolt, and 100 Ohm resistor together to use with one of the mini 12v batteries to power the LED. (I have little electronics knowledge - the RS guy helped me determine the resistor to use.)

When putting the battery, resistor, and LED together we found that it was supplying about 4.4 volts to the LED. When assembled in the flashlight, it is supplying about 3.3 volts. (I would assume the lower voltage is due to the resistance of the spring / bolt spacer used.)

Any suggestions on a different resistor to use to get the voltage up to the 4.5 volt (max) capabilities of the LED? Do I want to do that? / Would the increase in light output justify the stress on the LED? What can I expect for run times out of this battery?

Thanks in advance. This made a neat little pocket light – not quite as bright as one of the key chain LEDs, but then again, making one is much more fun than buying one!

Thanks, Slick. I tried it and it works. Appears to have a little more light output.

There ya go... All real modders exceed the rated specifications of various electronic components.