Electromagnetic Devices

Boxtop Loudspeaker

[M | t+ | ★★★★]
Make an amazing loudspeaker from a coil of wire, cardboard boxtop, and hand-held magnet.

Loudspeaker Microphone

[M | t+ | ★★]
Talk into a loudspeaker and amplify the induced current in the voicecoil.

Military Field Generator

[M | t | ★★★★]
Hand-cranked generator allows student to feel and appreciate power production when a small load (25 watt bulb) is connected.

Theremin

[M | t+ | ★★]
Your proximity to the instrument changes the capacitance and thus the resonance frequency of the oscillator.

Barlow's Wheel

[M | t+ | —]
A copper disk, supported between two magnet poles, rotates when a DC current is passed radially through it. 

Miller-Cowan Motor/Generator

[M | t | —]
Working model of electric motor and/or generator with solid and split-ring commutator.

Motor/Generator Pair

[S | t | —]
Two, small, permanent magnet, hand-cranked electric motors are wired together and operate interchangeably as motor or generator.

3-Phase Induction Motor

[M | t+ | ★★★]
Dramatic working model of induction motor.

Welding Transformer

[M | t+ | ★★★]
Step-down transformer with enough current to heat and fuse iron nails.
[In-Depth Description]

Transmission Line Transformers

[M | t+ | —]
15,000 volt step-up/step-down shows how high power can be transmitted along extremely small wire.

Tesla Coil

[M | t | —]
Extremely high voltages are generated by the application of a resonant circuit and tuned antenna.

Contact Us

Mailing Address: Lecture Demonstration Services, Science Center, Rm B-08A, 1 Oxford Street, Cambridge, MA 02138
Campus Location: Science Center B-08A | Tel: (617) 495-5824 | Email: scidemos-at-fas.harvard.edu