On Monday, September 9, 2013 11:07:02 AM UTC-4, Ian Field wrote:
"Phil Allison" wrote in message

...



"Ian Field = Fool"

Phil Allison



** LEDs are, believe it or not, DIODES !!



Having LEDs run on one half-phase of AC can cause flicker.



More importantly, you have to protect it on the alternate half-cycles,

the series resistor doesn't usually drop enough voltage at the reverse

leakage current to protect the typically 5V PIV.





** The spec of 5V is a nonsense.

Red LEDs take at least 9V reverse before any current flowed.

The white ones I have in stock took 22V with no current.

Getting away with a single static test is one thing - continuous repetitive
negative half-cycles might have a more tangible effect on LED life
expectancy.

Gotta agree with Phil, The 5V spec is nonsense. I haven't found an LEDs that (reverse bias) avalanche at any voltage less than 20V. If no current flows then what damage is done?

Phil, do you perhaps know the part number of the red LED that could only take 9V of reverse bias? I'd like to order some.

Oh.. most of the LED's I looked at took over 100 V of reverse bias till they avalanched.

George H.