🚀 go-pugleaf

The whole thread of `how to run X from a automobile battery should be in
a FAQ file.

The LM317 is a good chip for this sort of linear stepdown application.

BUT:
  the automotive alternator/battery/voltage regulator combination can produce
  violent transients, AND
  most power semiconductor devices fail shorted under these conditions

Do you really want to send the 140 V load dump or the 1500 V spike through
your homebuilt regulator into your $200+ portable stereo?  I didn't think so.
(:-)  The monolithic voltage regulator can only do so much.

You want at least a series fuse, a zener/MOV overvoltage protector, and some
RFI/EMI protection - the little microprocessor in a Discman gets confused easily.
Reverse voltage protection is nice, too.  Only about $2 for parts, too.

Could someone who has them accessable (= not under 1000Kg junk in attic) post
references to application notes, etc., describing the automotive electrical
environment?  I will as soon as I find mine, but that might not be soon...

	geoff steckel (gwes@wjh12.harvard.EDU)
			(...!husc6!wjh12!omnivore!gws)
Disclaimer: I am not affiliated with Sun Microsystems, despite the From: line.
This posting is entirely the author's responsibility.