"Steve B" wrote in message
...
Every once in a while, I need a 12 v. DC power source to trouble
shoot something. I have been using a battery charger, 12 v. around
6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe one of those power rescue jumper battery pack thinguses?
Kinda spendy, but sure I could score one at a yard sale. How do
they last? Very rechargeable?

Something with variable connectors for the times when you need a
clamp, or just a probe to put the juice at the right place.

Steve

I use these lab supplies:
http://www.caswellplating.com/electr...rectifier.html
http://www.microdaq.com/lascar/psu130.php
and an old Schauer battery charger to which I added a 3A Variac to set
the voltage and a 24,000uF filter cap. The original 6V/12V switch puts
the cap in the circuit when I need 12VDC and removes it for battery
charging, to avoid a spark and maybe blown fuse when I connect.

You could make an equivalent to the Lascar from an LM317 adjustable
regulator, but might not save much if you buy the meters etc new.