232
Electricity and Basic Electronics
Item
Plastic or fiber tubing, 3 1/2″ long with a
3/4″ to 1″ inside diameter
Plastic or fiber ends for tubing,
3″ diameter
Welding rods, cut to 4 3/4″ lengths
Toggle switch, 115-V, 15-A
Fuse, 8 A
Fuse holder
Male plug and lamp cord
Hookup wires, 4′ long
Magnet wire, 2 1/2-lb. No. 22
Lightbulb, 6 V
Magnet wire, 18-22 gauge, 30′ long
Aluminum tubing, 1 1/2″ diameter
Wood for base
No.
1
2
20
1
1
1
1
2
1
1
1
1
6 V bulb
18–22 gauge wire
B
A
White
wire
Black
wire
Fuse
8 A
SPST
switch
No. 22 magnet wire
110 V
AC
2″
Coil
Project 12-2: Repulsion
Coil (Continued)
9. Wrap 30′ of 18–22 gauge magnet wire
around a 2″ diameter pipe. Tape the wire
together and remove the pipe.
10. Solder the lightbulb to the coil.
When the project is completed, plug the lamp
cord into a 110-V electrical outlet. Drop the ring
of aluminum tubing over the core welding rods
and turn on the switch for the project. The ring
will shoot up in the air in a surprising demonstra-
tion of inductance. The energized coil induces a
current in the aluminum ring. A magnetic fi eld is
produced by the induced current. This magnetic
fi eld interacts with an opposing fi eld in the core
which repels the ring with such a force, it fl ies
into the air. If you were able to balance a heavy
ring that somewhat matches the opposing force,
you would have taken the fi rst step toward
magnetic levitation.
To further demonstrate the project, lower
the coil of magnet wire over the welding rod
core. The bulb will light up because you have
created a transformer. The bulb is the load. It is
now part of the secondary winding which was
placed close to the primary winding. Both wind-
ings are now sharing the same metal core.