What are Edison's four great inventions?

The inventor's four great inventions are the electric light, the phonograph, the talking movie and the moving movie projector.

1. Electric light: Edison was not the original inventor of electric light, but he made great improvements to it. After repeated experiments, he finally used tungsten wire as filament and invented an electric lamp with strong brightness and long life, which brought lasting and stable light to mankind.

2. phonograph: In 1877, Edison discovered that the diaphragm in the telephone transmitter would vibrate with the voice. He invented the phonograph through in-depth study of this phenomenon. The phonograph can record the sound and play it again at any time. This invention has completely changed the way people save and listen to the sound.

3. Movies with sound: In 191, Edison invented a movie camera which was composed of a phonograph and a camera, which was the embryonic form of movies with sound. This machine can record the sound and synchronize it with the image when it is shown, making the film a real audio-visual art.

4. Movable film projector: In 1891, Edison invented the movable film projector, which was an early film display device. It creates the illusion of activity by rotating the film strip with continuous pictures at high speed, which enables the audience to see the continuous pictures and lays the foundation for the popularization and development of the film.