Re: Q: for you 12V electrical wizzards.

"Ken Shackleton"
Joe Rooney wrote:
"Ken Shackleton" <
john wrote:
"XR650L_Dave" <is skeptical of the building better idiots every day
schools>
"Right....I was thinking of the effect on the LED, not the control
circuitry per se. I also assumed that the signal light [designed
for
12VDC] would be simply LED's and current-limiting resistors. Cheap
to
produce, simple, robust... "

I've long since stopped thinking "there's no way they'd build this
thing so it would break THAT easily!".

-DDave

reverse current goes to heat, i know my gas gas coil
does 100 watts + guessing led's that run on milli
amps wouldn't like to have all that juice running wild.
http://www.theledlight.com/pdf/NSPW500CS_18000mcd.pdf
5 volts @ 50 uA

I just read that link....the Vreverse is only 5 volts?? That is
exceptionally low. Ordinary diodes are typically in the hundreds of
volts for PIV. This would be the point at which the LED starts to
conduct in a reverse direction. This is much lower than I would have
guessed it to be.

Ken,

There are signs on the horizon that a silicon based LED may reach
manufacturing yields, but for now LEDs are made from III IV elements
gallium, aresenic, phosphor, and a bunch of other elements are used to
form
the junction. The diode is forward biased and when electrons move to a
lower energy band, they emit a photon of light.

The reverse voltage stinks and they also suffer from current crowding in
the
forward direction.

Interesting....Slocal...better talk to the manufacturer and see what
the Vreverse or PIV [Peak Inverse Voltage] is for your device.
Also...you might want to verify if your bike's voltage output is
regulated DC or AC.

I do have a nasty habit of sometimes typing before I am in possession
of all the pertinent facts....I apologize if I caused any confusion.

Ken


crud I was hoping you were right on the led's cause I was going to put a big
glob of them where my head light is <grin> then again I might just fix my
lighting coil then the RR I have off of a Honda 4 trax might have juice to
power up the (I can't see cause I'm getting chronologically challenged
optics)..
if I yank the coil off I might have to see if I can wind a few extra while
I'm in there and get the gazillion candle watt Baja type light for those
pesky woods where the trees play sun beam strobe on you.
john
bike is about down to two projects ahead of it... ya hoo


.

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