On Mon, 03 Oct 2011 19:51:39 -0500, Lloyd E. Sponenburgh wrote:

Ignoramus19762 fired this volley
in :


Brian Lawson is correct for a series circuit.


No, Ig. The point of highest power dissipation will be. Sorry, but
he's dead (old wive's tale) wrong.

If you had a "short circuit" with a resistance across the short of 10
ohms, and 220V across it, what would you get? (ok... rhetorical..) you'd
get a current of 22amps. 22 amps across 10 ohms would be 4840 watts.
That's a fair bit of heat.

Now "conduct" the same experiment with 10 gigaohms.

Tell me how much heat you generate, and whether or not it's discernable
against the background.

I think you're missing the point.

If you have a circuit with a 10 ohm resistance in series with a 1 ohm
resistance, and 30A flowing through the whole mess, then that's 9000W at
the 10 ohm, and only 900 at the 1 ohm. If they're both about the same
size, then the 10 ohm resistance is going to get 10 times hotter.

So if you have a dirty contact over _there_, and a dead short right
_here_, then the thing that's going to blow up is the thing over _there_.

All this being compounded by the ability of each resistance to dissipate
the heat. Hence the problems with aluminum wiring, where the fire
doesn't start in the lamp with the four 100W light bulbs dropping 110V
out in the air, but in the corroded connection that's dropping 10V buried
in a nice heat-insulating box.

--
www.wescottdesign.com