Massachusetts Institute of Technology
Sign in | Create Account

MIT Physics Demo -- Telegraph Transmitter

A solenoid enclosed in another solenoid is connected to a 12 volt battery. Also contained in the circuit is an iron contact switch connected to a spring arm, with a gap on one side of it. When the circuit is closed, the inner solenoid attracts the iron switch across the small gap. This breaks the circuit, making the switch move back to its original position, which closes the circuit again. Thus, the switch moves back and forth quickly, causing oscillations of high voltage in the outer solenoid. This high voltage causes sparks to jump the large gap between the ends of the outer solenoid.

These sparks cause electromagnetic radiation, which is how telegraphs were originally transmitted wirelessly. Morse code can be transmitted by opening and closing the power source.

This specific transmitter was made by the Marconi company, and is very much like the telegraph machine that would have been used on the Titanic. Read more about spark gap transmitters here.

Comments (2)

cool, very cool.

Posted almost 6 years by Anonymous User

spark gaps are also used as a means for modulating how much power can get through a circuit at a certain point.

Posted almost 6 years by Anonymous

You need to log in, in order to post comments. If you don’t have an account yet, sign up now!

MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated over 1 year ago

Created
April 10, 2008 13:56
Category
Tags
License
Creative Commons Attribution-NonCommercial (What is this?)
Additional Files


Viewed
49485 times

More from MIT Department of Physics Technical Services Group

MIT Physics Demo -- Jacob's Ladder and the Melting Nail

MIT Physics Demo -- Jacob's Ladder ...

Added over 6 years ago | 00:01:26 | 48037 views

Ripple Tank: Single and Double Slit Diffraction and Interference

Ripple Tank: Single and Double Slit...

Added 5 years ago | 00:03:05 | 57507 views

Temperature Effect on Resistance

Temperature Effect on Resistance

Added over 5 years ago | 00:01:10 | 42358 views

Bimetallic Strip

Bimetallic Strip

Added 2 years ago | 00:00:47 | 3274 views

Potential Energy to Kinetic Energy

Potential Energy to Kinetic Energy

Added almost 6 years ago | 00:01:11 | 30387 views

Interrupted Pendulum

Interrupted Pendulum

Added almost 4 years ago | 00:01:40 | 14743 views