20 Oct
2005
20 Oct
'05
2:37 p.m.
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