"Dave Plowman (News)" wrote:

In article . com,
wrote:
I'd not bother anyway. It's a red herring now. Might have been
relevant 50 years ago.


50 years ago there were no semiconductors in a car's electrical
system to worry about.


Far from. Alternators are still as inductive as they were, and a read
of National's app notes explains the whole thing and gives load dump
proofed circuits. Your kit may survive if you ignore it, but I'd say
the risks are significant.

I'm trying to think how many home made electronic additions I've got on
the old car - but it's lots. Things like a PDC. Electronic charge
indicator (useful with Lucas alternator) Timer for rear window. Better
controller for the central locking. 'One touch' electric window mods - and
sunroof too. And plenty others (I have a new car too and want some of the
toys on the old one and it's a hobby).

And none of them containing anything other than the usual smoothing and
decoupling. All using just basic op-amps, timers etc. And not one has
blown up. Perhaps it's because I didn't know about 'load dump' Now I do
they'll all start failing...


If your battery develops an open cell, or the cable falls off you'll
lose lots of electronics. Go to news:sci.electronics.design and tell
them that "Load Dump" in automotive electrical systems is a myth. They
will tell you just how wrong you are.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida