Each person at least once heard the word "cap." Usually it is pronounced in relation to various buildings. Builders know that a basement is part of the foundation that protrudes above the ground.
In other words, this is actually the foundation. However, in addition to construction, this term is used in relation to
electric lamps and even lamps. The base is a part of the design of the lighting device, necessary for its fixation in the cartridge, as well as for fixing the terminals-contacts. The easiest way to explain everything is the example of an
incandescent lamp, the appearance of which is known to absolutely everyone. By the way, in our country it is also known as the "Illich lamp".
Remembering the design
So, the lamp is a transparent glass or opaque flask, to which a metal tube with extruded thread is glued with a special heat-resistant resin composition. The base is this element. There are models in which it is made not of metal, but of ceramics, however these are special purpose lighting devices, therefore they are not common. The lowest part of the cap is a metal pad isolated from a threaded tube. One contact of the incandescent spiral is brought to it, and the other to the thread. It is enough to screw the lamp base into the lamp holder and apply voltage, as soon as a closed circuit appears and light appears.
Variety of standards
The specific use of lamps has led to the development of various types of socles. For example, it is obvious that a huge 500-watt bulb must be installed on the corresponding threaded tube. But in table lamps, where compactness is important, such "industrial" dimensions are completely inapplicable. Since the lamp base, which is more correctly called a “cartridge” (screwing into it), must correspond to the dimensions of this lamp element, a number of modifications were proposed and approved. All of them can be divided into two groups: with thread and pins.
Designations
The type of cap can be determined by the inscription applied by the manufacturer on the device body. It is a specific alphanumeric code, which is quite simple to decrypt. So, the most common are socles of type E27. Here, the letter “E” denotes a helical variety (derived from “Edison”), and the number “27” indicates the distance between two external opposite points of the thread.
The slightly smaller E14 size, better known as the Mignon, is often used in table lamps. And absolutely “kids” - E12 and E10 - are used in special lighting fixtures. Large industrial lamps are supplied with E40 socket types. Here is such a significant variation in thread diameters. But the cap of
fluorescent lamps, for example, are made on a completely different principle. For ease of installation and replacement, it was decided to replace the screw with pins. It is indicated, again, by a combination of numbers and letters. Instead of “E”, “B” is used, and the next number indicates the distance between the two pins. The design of the cartridge is made in such a way that the pins and pins when turning the lamp are fixed with special pressure plates, providing reliable electrical contact. The second name for this modification of the cap is bayonet. There is also a directly “pin” solution (modification “G”), when the leads are directly inserted into the cartridge without requiring rotation. This is often used in spotlights. Thus, the base is a whole system designed to fix the lamp and transmit electric current to its internal circuits.