||Radio Shack part number 270-401. This is a single AA battery
holder that is very handy to test if galvanometers are working. Just momentarily
touch power to the galvanometer contacts. If the needle jumps, it is good.
Warning: do not leave battery connected to galvanometer. Galvanometers have
very small wires and may not like lots of current passing through them.
You may even wish to put a resistor in series with the battery.
Another handy use is to power a camera when power must be connected then
removed several times. Saves the effort of installing/uninstalling the
standard camera battery repeatedly. Just clip one wire (on most cameras
this will be the holders red wire) to the frame using a test lead then
use the other holder wire (black) as a powered probe. I also have a two
AA battery holder I use for the same purposes. Radio Shack part number