The phonograph is a machine that plays records. Phonographs are also called record players. Until the mid-1980s, they were the most popular machine for listening to music. Today, most people have replaced their record collections with CDs and CD players. Some people still use phonographs to play their records.

The Invention

Thomas Edison invented the Phonograph in 1877. He made a machine that could record sound on a piece of tinfoil wrapped around a small metal cylinder and then replay the sound. The cylinder then went around on its axle, which was turned with a hand crank. A needle attached to a vibrating disc was placed against the cylinder. When someone spoke into the mouthpiece, the sound waves made the disc and needle vibrate. The vibrations made the needle make dents in the tinfoil on the cylinder. To play back the sound, another needle was attached to the cylinder. As the cylinder went around, the dents in the foil made the needle and diaphragm vibrate. The vibrations made sounds pretty much like the original sound. This was made without electrical energy and was called acoustic recordings.

How Phonographs Work

Phonographs played records made by analog disc recordings. An analog (which means likeness) of the original sound waves was stored as jagged waves in a spiral groove on the surface of a plastic disc. As the disc went around on the phonograph, a needle called a stylus moved along the groove. The waves in the groove caused the stylus to vibrate. These vibrations were then turned into electric signals that were changed back into sound by speakers.

 

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