MicroVAX II

From: Dave Woodman <dave_at_naffnet.org.uk>
Date: Sun Nov 24 04:13:00 2002

Jochen Kunz wrote:

> On 2002.11.24 01:20 Antonio Carlini wrote:
>
> No. The wires are connected in parallel. They have different lengths and
> thus different resistance - the longer the higher. "Current allways uses
> the way of lowest resistance." So the shortest wire has to carry a
> higher current than the other wires. The wire can carry this higher
> current, but the connector can't. So the _connector_ heats up and "the
> magic blue smoke escapes"...
> Solution was to use equal length wires (=equal current distribution
> among wires/connectors) and better connectors that can carry higher
> current.
> --

Let's try to keep this in accordance with real physical laws:- the current
flowing in the wires will be inversely proportional to the resistance since

the potential difference across them is the same. The physical principle
that causes the problem is that the power dissipated is proportional to the

*square* of the current. In case of any doubters -


     Ohms Law:
                  I = V/R

         => V=IR

     Power dissipated:
                 P = IV

         => P = I(IR)

So, for example, if one cable/connector pair had twice the resistance of
another, the second would dissipate four times as much power as the
first. If, as other posters have indicated, the bulk of the resistance is
in
the connector then the heating effect will be quite localised, and the
home cooking lessons are on.

        Cheers,

                Dave.
Received on Sun Nov 24 2002 - 04:13:00 GMT