Robert Lunn wrote:
>     User psychology.
>     [...]
>     Farmers, especially, are used to using car batt-
>     eries for all sorts of day-to-day purposes. They
>     are used, therefore, to having to worry about the
>     polarity of their connections.

I'm about to be a farmer.  (The Australian term for Farmer includes the
American term Rancher.)  Yes, having a piece of equipment without
polarity markings would be silly, but using a bridge rectifier might be
cheaper than a series diode in some cases.  I see these as separate
issues.

However, I'm worried that using a bridge would result in strange
potentials relative to vehicle ground, but I haven't thought about it
yet.

--
James Cameron                              (james.cameron@digital.com)
Digital Equipment Corporation (Australia) Pty. Ltd. A.C.N. 000 446 800