Robert Swinney wrote:
(top posting fixed)
"Tim Wescott" wrote in message
...
SteveB wrote:
My electrician friend came last weekend to do some work. He had this device
that looked like a large black crayon with a green conical end. About six
inches long, and as big around as a quarter.

He would put it close to a wire or a socket, and if it was hot, the green
light would come on, and a beep.

He said he thought they made them for 12v. automotive use. Anyone seen or
used these 12v. models?

Steve


Something like that works off of radiated emissions from the line, which
requires AC. It may work in a car if the engine is running, but don't
expect it to work with just a battery

Tim Sez: " . . .and no motors or noisy electronics
on the line. . . ."

How's about leaning on the horn while the tech has it up to his ear ?

Bob (don't know AC from DC) Swinney

I meant electrically noisy. An old-style vibrator horn would dump
plenty of electrical noise on the wire, but somehow I dunno if things
would work, even so...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html