3B Scientific Induction Tube Apparatus with 6 Coils User Manual

3B SCIENTIFIC® PHYSICS

Free-Fall Tube with 6 Induction Coils U8511200

Instruction sheet

12/09 SP/ALF

1 Free-fall tube
2 Coil
3 Connector sockets
4 Plinth with socket
5 Bar magnet
6 Cork mat

1. Description

The free-fall tube with 6 induction coils is used to
illustrate the principles of induced voltages.

The free-fall tube is a plastic tube that is mounted
upright on a plinth and has six identical induction
coils connected in series with one another. Within
the clamp socket of the plinth there is a rubber
washer, which prevents the falling body (a bar

magnet) from bouncing back up the tube after the
impact.

If the bar magnet is allowed to fall through the
tube, a voltage is induced in each of the coils in
turn. Since the velocity of the magnet increases with
time as it falls, the amplitudes of the voltage peaks
also increase as time passes, while their widths
decrease. The area under each of the voltage peaks
remains constant.

1

By using the 3B NETlogTM unit as an interface or by
means of a storage oscilloscope it is possible to
display the voltage curve graphically. Two 4 mm
sockets are provided for making the connections.

After falling, the magnet is held in the rubber
washer and can be retrieved when the plinth is
tilted sideways. The cork mat serves to protect the
magnet and the table top from damage by the
impact.

2. Technical data

Coil width: 5 mm
Distance between coils: 180 mm
Number of turns: 13 in each coil
Overall dimensions: 130x200x1020 mm

3

approx.

Weight: 500 g approx.

3. Assembly

• Set up the tube in the socket of the plinth using

gentle pressure.

Bumps, knocks or any lateral forces acting on the
tube may damage the instrument.

• Do not subject the tube to any mechanical

stress.

4. Operation

Also required:
1 3B NETlog

or
1 3B NETlog

1 3B NETlab

TM

U11300-230

TM

U11300-115

TM

U11310

Experiment leads

• Set up the experiment as shown in fig. 1.

• Connect leads between the connector sockets of

the tube and the voltage input U

IN

on the

A

interface.

• Connect the interface to the computer.

• Start the software program.

• Hold the bar magnet over the top opening of

the tube.

• Start a measurement in the program and allow

the bar magnet to fall.

• Evaluate the voltage curve.

Alternatively, the measurement may be carried out
with an oscilloscope.

Fig. 1 Experiment set-up

2