Re: ATM LED Brightness, was Sources for tester plans

["Pete Koziar" <pete.koziar@baltsun.com>]

Robert Duvall wrote:

Well, I've completed building my slitless tester, and had a few lessons
I wanted to pass on and get some feedback on.  Credit Robert Duvall for
the initial plans and help in this project.

First the light source, which there has been a great deal of discussion
over the past week or so.  I used a 5mm green LED coupled to a 9-volt
transistor battery with a 4.7kohm resistor in line.  The LED is mounted
in a hole drilled through 3/4" plywood, with a switch.  I placed a piece
of scotch tape over the business end to provide a flat diffuser surface.

<snip>

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If you want a MUCH brighter light, you can go down to 500 ohms for an LED
with your 9 Volt source (although I don't have my battery data sheets handy
to tell you what it will do to battery life -- you should still get a few
hours out of it, maybe as much as 10 with a good quality alkaline). Most
LEDs can handle 20 mA comfortably, I'm suggesting 18 and you're only
putting around 2 through it now. Brightness is roughly proportional to
current.



                         - Pete Koziar