In article ,
Jim Land wrote:
"An abrupt reduction in the alternator load causes a positive voltage
transient called "load dump." In a load dump transient the line voltage
rises to 20V or 30V in a few microseconds, then decays exponentially
with a time constant of about 100 microseconds. Much higher peak
voltages and longer decay times have also been reported. "The worst
case load dump is caused by disconnecting a low battery from the
alternator circuit while the alternator is running. Normally, this
would happen intermittently when the battery terminal connections are
defective. "Load Dump transients also occur when heavy loads are
switched off, although their magnitude and duration will be lower.
These transients are capable of destroying semiconductors on the first
'fault event'."

Given the number of semiconductors in use in the average vehicle - and
have been since the first transistor radio - it seems to be a problem that
has been solved...

--
*The more people I meet, the more I like my dog.

Dave Plowman London SW
To e-mail, change noise into sound.