On Apr 12, 5:24 pm, Charlie Morgan wrote:
Warning to all onlookers: w_tom is a well known usenet kook.

Charlie Morgan suggested using "an LM7812 voltage regulator at each
instrument you want to protect." when it is only rated for about 35
volts input. If Charlie was posting with technical knowledge, then he
knew the 78xx series has long been insufficient for mobile operation.
The OP has a choice. Either believe a poster who cites professional
standards and knows the 7812 as a defective solution. Or believe the
person who uses insults and personal attacks to prove superiority.

The 7812 recommendation is repeatedly bogus.
1) Its maximum input voltage is 35 volts.
2) It requires more than 14.5 volts input to maintain 12 volts
output.
3) Anything a 7812 might accomplish is already inside electronics.
4) Even National Semiconductor, that also manufacturers a 7812,
instead recommends other voltage regulators for mobile service. If
Charlie Morgan had basic technical knowledge, then he might have
recommended products from National's automotive line. He did not even
know basic electrical information.

Charlie Morgan again posts personal insults. His own post is in
error for above four reasons - and numerous others. Who is the kook?
One who recommended solutions, numbers, AND industry standards? Or
one who foolishly recommended the 7812 because he never read
manufacturer datasheets nor learned basic facts?

If Charlie Morgan had technical knowledge - and he clearly does not
- then he could have recommended this voltage regulator that actually
claims load dump protection, reverse voltage protection, and low
dropout voltage:
http://www.national.com/pf/LM/LM2931.html

But then Charlie did not even know what load dump is. All posts
from Charlie are suspect as technically naive - as demonstrated again
here.

Previously Charlie attacked another poster who only asked what DSL
filters do. Charlie. He asked whether it was a high pass or low pass
filter. Charlie replied, "yes" and proceeded to insult that poster.
His entire technical reply was to mock that poster. Nothing new in
Charlie's behavior here. His personal superiority means we can ignore
his 100% defective 7812 recommendation?

Charlie Morgan posts are not to be trusted. How does one know? He
does not even know the limits of a simple 7812 regulator. His entire
technical reply is justified by personal insults. I expect him to
continue with those insults. Charlie does not like it when we learn
how little he actually knows. He did not even know something so well
understood as load dump.