[AT] Ford 8n Under Dash Resistor?

[Stephen Offiler]

On Wed, Jan 7, 2009 at 1:41 PM, Mike Sloane <mikesloane at verizon.net> wrote:
> Well, there is another "fly in the ointment": resistance in a wire is
> also dependent on temperature. If you don't use a heavy enough wire, it
> will heat up, and the resistance (and the voltage drop) will change.

Very true.  Copper wire increases resistance by 0.4% per degree C, and
the insulation is typically rated at 90C.  That's about 70C above a
"room temperature" ambient, so, we're talking about a total resistance
rise of about 28% before the insulation starts to melt (obviously,
bad).  So, choose a heavy enough wire that the insulation doesn't
melt, and you should be able to create a "resistor" that doesn't
change so much that you need to worry about it.

>... But
> heavy wires have less resistance than thin ones.

Right.  So, it means you need to use a longer length of thicker wire.
That's why I originally said you can SOMETIMES use this technique;
there will be times that the length and gage of wire just isn't
practical.

Steve O.