HOW TO TEST YOURSELF
The testing device consists of four parts
the test surfaces, probe and handhold, speaker, and circuit.
These are connected by leads. The first item to construct is the
Test Surfaces
Test Surfaces
You will need two
plates to set test samples
on. The plates that hold
the samples are inten-
tionally separated from
The Easy Way Circuit
unless you add shield-
ing, the frequencies on
the test plates may inter-
fere with the circuit.
Materials needed:
shoe box
aluminum foil
stiff paper
2 bolts and nuts
nail
4 alligator clip test leads (3
very short, 1 about 24
inches)
2 ordinary light switches.
Acceptable:
Cut two 3½ inch
squares out of stiff paper such as a cereal box. Cover them with
slightly larger squares of aluminum foil, smoothed evenly and
Fig. 82 Test surfaces