In article ,
George E. Cawthon wrote:
Don Klipstein wrote:
In article ,
George E. Cawthon wrote:
Tell us how many of the bulbs failed at the end of
the Christmas season. Last year, I bought a
package of nightlites (cycle a series of colors)
that I bought from Costco (not cheap). Out of 5
only the two that we kept still work.

A nightlight with cycling colors has the added color-cycling circuitry,
which could be what failed. If a multicolor nightlight died in full, I
would not blame the LEDs.

- Don Klipstein )
Possible. I recently bought a little key chain
light that stopped working after a short period.
Wouldn't work with new batteries. Putting power
directly to the led connectors wouldn't light it
either.

Possibly you had a weaker-than-usual LED and/or a battery with less
internal resistance than usual and burned out the LED. LED keychain
lights usually don't have resistors or anything else besides the internal
resistance of the battery to limit the amount of current flowing through
the LED. Resistors (or other current limiting means) are normally
considered necessary with LEDs to keep them from drawing excessive current
and overheating.

Possibly the LED may have suffered static damage if the light was
exposed to static electricity. Many white and blue LEDs are
static-sensitive. However, in my experience so far, static-zapped white
and blue LEDs mostly work with some loss of light at full current or
moderate overcurrent, which is typical of keychain lights with fresh
batteries. Static-damaged white and blue LEDs typically have a complete
loss of light output when lower current (a few milliamps) is used.

- Don Klipstein )