Marechiare wrote:
> It looks like he did not start learning electronics yet. You seem to
> have missed his [OT] post:
>
> On Sun, Jul 5, 2009 at 8:49 AM, solarwind wrote:
>> People say current kills. So what happens if you push 1 mA through an
>> LED @ 1000 V? Will the LED blow?

I don't read OT.  I am surprised however as I thought he was farther along
than this.

Solarwind, look up something called Ohm's Law.  It defines the relationship
between voltage accross a device, the current thru it, and its resistance.
In this case you don't control the characteristics of the LED, so you only
get to chose one of current thru it or voltage accross it and it will pick
the other.  You can't therefore push 1mA thru a LED (or any other device)
while at the same time applying 1000V accross it (unless that device happens
to be a 1Mohm resistor).

At 1mA thru it forwards, you'll get around 2 to 2.5 volts accross most
normal red or green LEDs, and it will light dimly but visible enough in a
typcial office setting.  At 1mA backwards the LED is being driven in a
unintended way so results will vary more widely.  You probably get 5-20V
before it no longer acts much like a diode and allows 1mA of reverse
current, but I haven't tried that so my guess could be off.

Conversely when you apply 1000V in either direction, the LED will draw way
more than 1mA for a very short time before it makes a popping noise and
emits a small mushroom cloud.  What happens after that, including arcing and
possibly catching fire is too dependent on the particulars of the LED,
humidity, and random chance to guess.  Let's just say it would be
"spectacular".  Once.


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