November 21, 1877
Thomas Edison announces his invention of the phonograph, a machine that can record and play sound.
Photograph of Edison with his phonograph, taken by Mathew Brady in 1877
The phonograph record player, or gramophone (letter + sound) is a device introduced in 1877 that continued common use until the 1980s for reproducing (playing) sound recordings, although when first developed, the phonograph was used to both record and reproduce sounds. The recordings played on such a device generally consist of wavy lines that are either scratched, engraved, or grooved onto a rotating cylinder or disc. As the cylinder or disc rotates, a needle or other similar object on the device traces the wavy lines and vibrates, reproducing sound waves.
December 31, 1879Thomas Edison demonstrates incandescent lighting to the public for the first time, in Menlo Park, New Jersey.
It was during this time that he said: "We will make electricity so cheap that only the rich will burn candles."
, incandescent lighting
, New Jersey
February 13, 1880Thomas Edison observes the Edison effect.
Thermionic emission (Edison effect) is the heat-induced flow of charge carriers from a surface or over a potential-energy barrier. This occurs because the thermal energy given to the carrier overcomes the binding potential, also known as work function of the metal. The charge carriers can be electrons or ions, and in older literature are sometimes referred to as "thermions". After emission, a charge will initially be left behind in the emitting region that is equal in magnitude and opposite in sign to the total charge emitted. But if the emitter is connected to a battery, then this charge left behind will be neutralized by charge supplied by the battery, as the emitted charge carriers move away from the emitter, and finally the emitter will be in the same state as it was before emission. The thermionic emission of electrons is also known as thermal electron emission
, thermionic emission
February 19, 1878Thomas Edison patents the phonograph.
The phonograph record player, or gramophone, is a device introduced in 1877 that has had continued common use for reproducing (playing) sound recordings; although when first developed, the phonograph was used to both record and reproduce sounds. The recordings played on such a device generally consist of wavy lines that are either scratched, engraved, or grooved onto a rotating cylinder or disc. As the cylinder or disc rotates, a stylus or needle traces the wavy lines and vibrates to reproduce the recorded sound waves. The phonograph was invented in 1877 by Thomas Alva Edison at his laboratory in Menlo Park, New Jersey, USA. On February 19, 1878, Edison was issued the first patent (U.S. patent #200,521) for the phonograph.