1 LED & 3AAA Batteries

Can somebody suggest best resistor configuration for an
ultra slim pen-type light I am designing....

Giving battery typical drain values what resistor values should I use / how many hours will I approximately get
given the following Scenario:

I will be using just 1LED
- 1 3.6-4V Nichia 5mm White/Green or Blue

Given the design I am hoping to use:

3no AAA Alkalines.
- giving 4.5 volts
or 3no 1.2V AAA Nimh
- giving 3.6V

Current requirement at avg. battery voltage needs to be 20mA
Initial Current can be higher if required - heat sinking is built into the design.

Any suggestions?

Thanks.

NEWLAMPS..
PS I offer all candlepower members:
- Best-Bin* Nichia...US$1dollar eachor less!
-------Based on 25 pieces.
-------Excluding. shipping from Europe @ cost.

* Best Bins = S or T grade.

Hi newlamp,

Welcome to CPF!



About your light, are you aware of the Streamlight Stylus ?


I'm not sure if it is resistored, (most people tend to overdrive their leds) but if you ask around here I'm sure someone will have the answer for you. /ubbthreads/images/graemlins/wink.gif

You can always calculate the resistor needed with this formula: R=V/I wher R is the resistance , V the voltage and I the current.

About offering stuff for sale, please read the Advertizing policy on CPF.

Have fun! /ubbthreads/images/graemlins/grin.gif

I am going to try a 37ohm resistor with 3no 1.5V AAA Alkalines. have no idea how well this will work once the batteries start to fade...but we are talking about just one LED here and I believe alkalines hold their power well?