Make Electronics

Getting Somewhat More Serious 97

Shopping List: Experiments 12 Through 15

Figure 3-4. As long as you treat it carefully,
a cheap set of plastic magnifying lenses is
perfectly acceptable. Handheld magnifica-
tion is essential for inspecting the solder
joints that you make on perforated board.

Figure 3-5. This kind of folding magni-

fier can stand on your desktop and is

useful for checking part numbers on tiny

components.

Essential: Clip-on meter test leads
The probes that came with your multimeter require you to hold them in
contact while you make a reading. This requires both hands, preventing
you from doing anything else at the same time.
When you use a pair of “minigrabber” probes with little spring-loaded
clips at the end, you can attach the Common (negative) lead from your
meter to the negative side of your circuit and leave it there, while you
touch or attach the positive probe elsewhere.
The Pomona model 6244-48-0 (shown in Figure 3-6) from Meter Superstore
and some other suppliers is what you need. If you have trouble finding it
or you object to the cost, you may consider making your own by buying a
couple of “banana plugs” (such as RadioShack part 274-721) that will fit the
sockets on your meter, and then use 16-gauge or thicker stranded wire to
connect the plugs with IC test clips, such as Kobiconn 13IC331 or RadioShack
“mini hook clips,” part number 270-372C. See Figures 3-7 and 3-8.

Figure 3-6. These “minigrabber” add-ons for
meter leads make it much easier to measure
voltage or current. Push the spring-loaded
button, and a little copper hook slides out.
Attach it to a wire, release the button, and
you have your hands free for other tasks. It’s
a mystery that meters are not supplied with
these grabbers as standard equipment.

Figure 3-7. To make your own minigrabber

meter leads, first attach a banana plug to

a wire by sliding the wire through the cap,

into the plug, and out through a hole in

the side.

Figure 3-8. Then screw a collar over the

protruding piece of wire, and screw on the

cap. The other end of the wire is soldered to

a probe.