Edison (1847 ~ 1931) was a famous American inventor. He was studious, good at thinking and hard working all his life. At the age of 75, he also signed in for work in the laboratory on time every day. He worked almost ten hours a day for decades and read books in the study for three to five hours at night. If the average person's life activity time is used to calculate, his life has been doubled. Therefore, on his 79th birthday, Edison proudly told people that I was 135 years old. He lived to be 84 years old, and there were as many as 1,1 inventions in his life, among which the greatest contribution was to invent the phonograph and the automatic telegraph, and to experiment and improve the incandescent lamp and telephone. Edison began to study electric lamps in his early twenties, which lasted for more than 1 years. He chose thousands of different substances such as bamboo cotton, graphite, tantalum, etc. as filament materials for experiments, and he often learned a lot. Once he and his assistants worked continuously for 5 days and nights. In 1879, Edison used carbon filament as incandescent filament and lit it for 4 hours. Because the surface of carbon wire is porous and brittle, its strength is very low. It was soon replaced by tungsten wire.

in 1883, Edison discovered the thermionic emission phenomenon, also known as the "Edison effect", that is, some electrons or ions near the surface of a metal gained enough kinetic energy due to their irregular movement due to high temperature, which overcame the constraints of the surface and escaped from the metal. Edison effect is very important for the operation of all vacuum tubes. As the emission surface, the cathode is often coated with a layer of alkaline earth metal oxide to facilitate electron emission and heated by current to maintain high temperature.

in 19, Edison invented the iron-nickel battery, which is an alkaline battery with an electromotive force of about 1.3 ~ 1.4 volts, long life, but low efficiency. Edison had many inventions in his life, but when someone asked him why he succeeded, he said: Some people think that I have any genius, which is not correct. "Genius" is one percent inspiration and ninety-nine percent perspiration.