[TriLUG] [OT]: Best RadioShack (or equivalent) in RDU

[Brian Henning]

John Riselvato wrote:

> I'm looking for low voltage blue LEDs, a two AA
> battery holder/case, switch and resistors that would interface correctly
> with the LEDs.

John, I can't address RS's stock status, but I wanted to chime in for this
reason:

Be aware that most discrete through-hole blue LEDs have forward voltage
drops nearing or over three volts (2.7V for 3mm, 3.2V for 5mm).  You might
want to consider powering your project with a 9-volt battery instead of a
pair of AAs (only ~2.4V if you use rechargables).

(Skip the next part if you're already familiar with Ohm's law to find the
appropriate resistor for a given LED)

For a typical 3.2V blue 5mm LED with 20mA forward current and a 9-volt
battery, you'll need a resistor as follows:

9V - 3.2V = 5.8V across the resistor
5.8V / 20mA = 290 ohms

Hope this helps, and good luck!
~Brian