ATM A little electronic help on my Foucault tester

["James Taylor" <u2pilot@satx.rr.com>]

I'm about to build my tester.  I need some electronic help.

I'm planning to use one of the Radio Shack bright (and big) LEDs.  All I
need to know is how do I wire it so that I don't burn it out.  I want to run
it off batteries and put a pot on it so I can dim it if needed.  I took the
Heathkit Home Electronic course waaaay too long ago to remember anything
useful out of it.

Which one I should use is another discussion.  Right now I'm looking for
some electronics advice.

Here are the LED specs off the back of the package(s).

The Orange one:  Normal ops is 2V and 40mA.  300mcd

Green: normal ops 2.2V, 40mA. 350mcd

Super Bright White: 1.82V +/- .03V and 20mA.  This baby puts out 5000mcd at
660nm wavelength.

There were some peak voltages and amps associated with them, but I thought
the nominal values were probably enough for this question and I didn't write
them down.

Oh, last thing.....what is the mcd unit given on those packages?  I was
expecting to see Lumens or something similar.

James