[sdiy] how to double Si diode voltage rating

[KA4HJH]

>With LEDs there's some other factor limiting the current,  typically an
>external resistor (though I have run across some that appeared to have
>internal current-limiting,  they'd run just fine on 5-12VDC with little
>change in brightness,  but that's another story).

I've seen some stuff that has eight or ten of them in parallel with a
single resistor in series. At some point, especially if the current is
fairly high, it could lead to a cascade failure.

I've also seen different colors in parallel. Not a great idea, either, what
with the varying forward drops. Of course all this is cheap consumer crap.
I'm not particularly worried about it, it might last for years. But it's
lousy design and I've seen enough of that lately.

>With rectifiers,  one will take more current than the other,  unless you put
>something in there to even things out.  And the hotter one will have a lower
>voltage drop since a forward-biased junction has that kind of a temperature
>coefficient,  which means that it'll tend to hog more of the current,  and so
>forth,  until something fails.

Exactly.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

"You'd PAY to know what you REALLY think"--Dobbs