Replacing Old LEDs

[Paul Koning]

>>>>> "Chuck" == Chuck Guzis <cclist at sydex.com> writes:

 Chuck> 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.?

 Chuck> If you're talking about vintage garden-variety red or green
 Chuck> LEDs, just pick replacements with the same size and color. 

That should work for yellow and orange too.  But (unlikely case in
vintage gear) it may give you trouble for blue, since there are at
least two very different semiconductors in blue LEDs: silicon carbide,
and some III/V compound (GaP?  GaN?) which almost certainly have
different forward drops.

    paul