Atlantic Illumination Entertainment Lighting AIEL Instructional STAGE LIGHTING SOCKET GUIDE This Article will Discuss the Various Socket Types used in Stage Lighting Fixtures THE FOLLOWING MAY NOT BE REPRODUCED WITHOUT PERMISSION FROM THE AUTHOR © Topics Preliminary Socket Materials Socket Types Reference Table PRELIMINARY The most important component of a stage lighting fixture is its electrical socket. Without it, most lamps cannot be held correctly, and, screw terminals and ferrule contacts excluded, none would have the electrical connections needed to emit light. Various sockets have been developed over the years to provide the proper connection, orientation, and filament height, along with the mechanical abilities to hold the lamp and to dissipate some portion of the heat transmitted or radiated toward the socket. At least some of these different versions were only made because patents of a given socket type prevented usage by rival companies. Here is an initial article that will discuss socket aspects in regards to the fixtures that use non-LED lamps. This will be followed by a reference table that gives the typical lamp base types with their common names and their IEC (International Electrotechnical Commission) scoket designations. SOCKET MATERIALS Electrical sockets grew out of connectors for some lamps that had only screw terminals to attach the lamp to its voltage source. This method is still seen today in rough-service situations such as marine and railroad applications. Sockets came about as a way to quickly replace failed lamps, and as an alternate method to hold the lamp in place. These sockets were originally made from metal with a cardboard insulator. Some very cheap sockets that used low-wattage, low-heat sources were made of metal that was insulated with wax! (These could still be seen as late as the 1950s in some parts of the world.) Later, an early type of plastic, Bakelite, began to be used; it, or a similar material is still employed today in low-wattage, typically residential, fixtures. However, as light and heat output increased in lamps designed for performance and other demanding purposes, socket insulators began to be made of porcelain because other materials deteriorated too easily from heat. These are often encased partly or completely in metal for strength and heat-dissipation purposes. SOCKET TYPES Although lamp manufacturers work to improve existing products, new ones also come about because of the innovative methods of the fixture designers themselves. They want smaller fixture bodies with more efficient optics. This is especially true in projection and medical equipments; these demand more compactness coupled with new techniques of directing light to where it is desired. So new socket types must also be developed. The following table explores both old and new ones. SOCKET REFERENCE This table focuses on sockets used in entertainment industry equipment. Be aware that some sockets appear more than once because the table is cross-referenced. Note that there are variations of many of these sockets as seen by those in other professions, and that they have different International Electrotechnical Commission (IEC) designations. To directly locate a Socket without scanning the table, please use your browser's built-in "Search" function. For information regarding this feature, go to Intra-Page Search) Socket Reference Table Lamp Base IEC Socket and Description Designation Bayonet: Single-Contact BA15S Bayonet: Double-Contact BA15D Bi-Pin: MR8, MR11 GU4, GY4, GZ4 Bi-Pin: Medium G9.5 Bi-Pin: Prefocus G29.5 Bi-Pin: Medium Prefocus GY9.5 Candelabra: Miniature (MiniCan) E11 Candelabra: Screw E12 Double-Ended R7s Extended Mogul End Prong GX16d Medium Bi-Pin G9.5 Medium Bi-Pin, Prefocus GY9.5 Medium Prefocus PS20 Mogul Prefocus P40s Medium Side Prong G16? Medium Screw E27 Medium Two-Pin GY9.5 Miniature Candelabra (MiniCan) E11 Miniature Screw E10 / G4.5 Mogul Bi-Post G22 Mogul End Prong GX16d Mogul End Prong, Extended GX16d Mogul Prefocus P40s Mogul Screw E39 Prefocus, Bi-Pin G29.5 Prefocus, Bi-Pin, Medium GY9.5 Prefocus, Candelabra ? Prefocus, Medium PS20 Prefocus, Mogul P40s Screw, Candelabra E12 Screw, Intermediate E17 Screw, Medium E27 Screw, Miniature E10 / G4.5 Screw, Mogul E39 -------- Ferrule Contacts (No actual socket) ----- Screw Terminals (No actual socket) ----- _________________ Reference: http://AIEL.chebucto.biz/Market/Socket.html