Electric light be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. The three main categories of electric lights are incandescent lamps, which produce light by a filament heated white-hot by electric current, gas-discharge lamps, which produce light by means of an electric arc through a gas, and LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor. Before electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, and fires. Cornish chemist Humphry Davy developed the first incandescent light in 1802, followed
The Electric Light Orchestra (album) The Electric Light Orchestra (album) The Electric Light Orchestra is the eponymous debut studio album by English rock band Electric Light Orchestra (ELO), released in December 1971 in the United Kingdom by Harvest Records. In the United States, the album was released in early 1972 as No Answer, after a misunderstood telephone message made by a United Artists Records executive asking about the album name; the caller, having failed to reach the ELO contact, wrote down "no answer" in his notes, and this was misconstrued to be the name of the album. The album is focused on the core trio