Replacing Old LEDs

[Chuck Guzis]

On 10/20/2005 at 3:45 PM Bradley Slavik wrote:

>I regret that my EE knowledge was never deep and is
>a little rusty now. I am refurbishing some old PC
>boards and wanted to replace a few of the LED which
>had become damaged or broken off. Here is my lame
>question, how do I correctly pick replacement LEDs?
>I know colors, and size, but how do I make certain
>that I have picked correct wattage, etc.?

If you're talking about vintage garden-variety red or green LEDs, just pick
replacements with the same size and color.  In general, LED's today are
more efficient than the old ones and offer a wider choice of illumination
angles but newer ones should work just fine as replacement for the
antiques.  Most red LED's still exhibit a forward voltage drop of about 1.6
volts and the practice is to insert a current-limiting resistor in series
with the diode, so your risk is negligible.

Cheers,
Chuck