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
Hartford Electric Light Company There were about 20,000 ranges put into homes throughout the Hartford area. HELCO's president received patents for an electrical radiator to heat water and an ice-making machine. Many of the homes of Hartford had these electrical appliances by 1915. The original property at 266 Pearl Street is within the Ann Street Historic District and is now the Connecticut Light & Power Company. Hartford Electric Light Company The Hartford Electric Light Company (HELCO) is a defunct electrical company that was located on Pearl Street in Hartford, Connecticut. It was merged with the Connecticut Power Company in 1958 and later these became