On Sat, 02 Feb 2008 08:14:06 -0600, "Pete C."
wrote:

Don Foreman wrote:

On Fri, 01 Feb 2008 20:37:00 -0600, "Martin H. Eastburn"
wrote:

Why not a voltage regulator or better yet - a 12V DC to 6V DC switcher.
There are lots of power supplies like this about the size of a hand
or less.

Martin

Might be a radio noise issue with an AM radio. Some of the "simple
switcher" chips are very easy to use, though. I've built little
switchers by epoxying parts on the back of a wallwart -- no circuit
board at all, just haywire things and then glop 'em good.

AM radio???

Certainly a switching supply would be more efficient than a linear.
Who's worrying about efficiency? We are talking dissipation of
something like 3 watts maximum using a resister, and something less
than that with a linear IC.
POWER efficiency might be better with a switcher, but by the time you
adress the RF implications your total cost/benefit ratio would kinda
outweigh the benefits.


To stay with the "era" of the car, he can go to NAPA and order a
VT6188 or VT6187 Voltage reducer. It is a 1.5 ohm resistor for use on
a 4 amp maximum load. The 6188 is a 6187 with a mounting bracket.

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