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From Edison’s Filament to the Digital Age
The story of the Transistor
American businessman and inventor Thomas Alva Edison (1847–1931) was renowned for his legendary obstinance in problem-solving. He conducted more than 2,700 experiments to develop a working incandescent lamp, reportedly trying over 6,000 different materials to find the right filament for his light bulb. When questioned about his numerous failures, Edison famously remarked: “I have not failed 10,000 times — I’ve successfully found 10,000 ways that will not work.”
During his experiments, Edison observed a phenomenon called ‘thermionic emission’ or what is referred to as the ‘Edison effect’ — when high voltage is applied between a heated filament and a nearby metal plate, a current flows between them. Edison patented his discovery in 1883, one of the first patents filed for an electronic device.
The effect was further explored by John Fleming (1849–1945), an English electrical engineer and physicist who developed the first functional vacuum tube based on Edison’s observations in 1904. He invented the ‘thermionic valve’ or ‘Fleming diode’ — a vacuum tube that worked as a ‘rectifier’, converting alternating current (AC) into direct current (DC) by allowing current to flow in only one direction.
