Edison screw

Edison screw (ES) is a standard <a href="/facts/Lightbulb_socket/c0mHjo9E">lightbulb socket</a> for <a href="/facts/Electric_light/v3fb5WBp">electric light</a> bulbs. It was developed by <a href="/facts/Thomas_Edison/IeDbdyP4">Thomas Edison</a> (1847–1931), patented in 1881, and was licensed in 1909 under General Electric's <a href="/facts/Mazda_(light_bulb)/RqM9V7Ky">Mazda</a> trademark. The bulbs have <a href="/facts/Screw_thread/dqGzDfHv">right-hand threaded</a> metal bases (caps) which screw into matching threaded sockets (lamp holders). For bulbs powered by <a href="/facts/Single-phase_electric_power/fVr79Kjy">AC current</a>, the thread is generally connected to <a href="/facts/Ground_and_neutral/uFo5TAKh">neutral</a> and the contact on the bottom tip of the base is connected to the "live" phase.
In North America and continental Europe, Edison screws displaced other socket types for general lighting. In the early days of electrification, Edison screws were the only standard connector, and appliances other than light bulbs were connected to AC power via lamp sockets. Today Edison screw sockets comply with international standards.
Their types are designated as "Exx", such as "E26", where "xx" indicates the diameter of the socket in millimeters.

Edison screw open-in-new

Edison screw