<P> Edison used the carbon microphone concept in 1877 to create an improved telephone for Western Union . In 1886, Edison found a way to improve a Bell Telephone microphone, one that used loose - contact ground carbon, with his discovery that it worked far better if the carbon was roasted . This type was put in use in 1890 and was used in all telephones along with the Bell receiver until the 1980s . </P> <P> In 1878, Edison began working on a system of electrical illumination, something he hoped could compete with gas and oil based lighting . He began by tackling the problem of creating a long - lasting incandescent lamp, something that would be needed for indoor use . Many earlier inventors had previously devised incandescent lamps, including Alessandro Volta's demonstration of a glowing wire in 1800 and inventions by Henry Woodward and Mathew Evans . Others who developed early and commercially impractical incandescent electric lamps included Humphry Davy, James Bowman Lindsay, Moses G. Farmer, William E. Sawyer, Joseph Swan, and Heinrich Göbel . Some of these early bulbs had such flaws as an extremely short life, high expense to produce, and high electric current drawn, making them difficult to apply on a large scale commercially . Edison realized that to connect a series of electric lights to an economically manageable size and using the necessary thickness of copper wire, he would have to develop a lamp that used a low amount of current . This lamp must have high resistance and use relatively low voltage (around 110 volts). </P> <P> After many experiments, first with carbon filaments and then with platinum and other metals, Edison returned to a carbon filament . The first successful test was on October 22, 1879; it lasted 13.5 hours . Edison continued to improve this design and on November 4, 1879, filed for U.S. patent 223,898 (granted on January 27, 1880) for an electric lamp using "a carbon filament or strip coiled and connected to platina contact wires". This was the first commercially practical incandescent light . </P> <P> Although the patent described several ways of creating the carbon filament including "cotton and linen thread, wood splints, papers coiled in various ways", it was not until several months after the patent was granted that Edison and his team discovered a carbonized bamboo filament that could last over 1,200 hours . The idea of using this particular raw material originated from Edison's recalling his examination of a few threads from a bamboo fishing pole while relaxing on the shore of Battle Lake in the present - day state of Wyoming, where he and other members of a scientific team had traveled so that they could clearly observe a total eclipse of the sun on July 29, 1878, from the Continental Divide . </P>

When did the first light bulb get invented