[sdiy] LED driver cable length

[Harry Bissell]

I had an industrial problem where ESD killed TWO THOUSAND VOLT DIODES !!!

yes, your fingertip is death. Very freaky and not what you would expect. Once in a circuit
the other components might protect them. Probably bypassing them with a 100pF cap would
work, but then spikes on my 480V line might leak through, rwach out, and (T)OUCH someone...

I've had many dead withe LEDs, never a red one.

H^) harry


----- Original Message -----
From: Barry Klein <Barry.L.Klein at wdc.com>
To: Tom Wiltshire <tom at electricdruid.net>
Cc: synth-diy DIY <synth-diy at dropmix.xs4all.nl>
Sent: Mon, 12 Sep 2011 16:44:46 -0400 (EDT)
Subject: Re: [sdiy] LED driver cable length

Seriously.  I'm commenting from experience.
First, handling them killed them by me and the factory.  Anything above 10V
can kill them - that includes ESD from getting up from your non-ESD padded
chair.
CMOS has ESD protection, LED's don't.  9V is within the CMOS 4000 series
input tolerance.  ESD is not.
You want more?  Try measuring the EMP pulse on the long wire when lightning
hits nearby...

Barry




-----Original Message-----
From: Tom Wiltshire [mailto:tom at electricdruid.net] 
Sent: Monday, September 12, 2011 1:31 PM
To: Barry Klein
Cc: synth-diy DIY
Subject: Re: [sdiy] LED driver cable length


On 12 Sep 2011, at 19:49, Barry Klein wrote:

> You could get a transient inductive pulse through the cable upon 
> connect/disconnect that could overvoltage the LED.

Seriously?

Isn't this one of those "you could"s that is really a "..but you *could* win
the lottery"?

> Also ESD is something to worry about - especially if using white/blue
leds.

Again, ESD blowing up LEDs? I've never even managed to blow up a CMOS 4000
series using ESD. And I did try, although I don't wear many artificial
fabrics. A 9V battery was required, and even then I had to do it wrong. Now
*that* works for LEDs too.

I'm not really trying to knock what is probably technically correct advice,
but it just sounds all rather over the top for what is just an LED at the
end of a long wire. It's not like we're running a life-support machine off
this jack lead. The worst case is the synth player has to wave his hand in
time in the unlikely situation that the LED boxes die.

T.

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-- 
Harry Bissell & Nora Abdullah 4eva