The cap is part of the lamp

Everyone at least once heard the word "socle". Usually it is pronounced in relation to various buildings. Builders know that the basement is part of the foundation that protrudes above the ground level. In other words, this is actually the basis. However, in addition to construction, this term is used for electric lamps and even lamps. The plinth is a part of the design of the lighting device, which is necessary for fixing it in the chuck, and also for fixing the pins-contacts. The easiest way to explain everything on the example of an incandescent lamp, the appearance of which is known to absolutely everyone. By the way, in our country, it is still known as the "Ilyich bulb".

Remembering the construction

So, the lamp is a glass transparent or matte flask, to which special metal-resistant resin compound is glued a metal tube with extruded thread. The base is this element. There are models in which it is made not of metal, but of ceramics, but these are special-purpose lighting devices, so they are not widely distributed. The lowest part of the socle is a metal pad, isolated from a threaded tube. It has one contact of the filament of incandescence on it, and the other one on the thread. It is enough to screw the lamp cap into the lamp holder and apply voltage, as a closed circuit will appear, and light will appear.

Variety of standards

The specificity of the use of lamps led to the fact that different types of socles were developed. For example, it is obvious that a huge bulb of a 500 W incandescent lamp should be installed on a suitable 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 the "cartridge" (it is screwed into), must match the dimensions of this lamp element, a number of modifications have been proposed and approved. All of them can be divided into two groups: with thread and pins.

Notation

The type of socle can be determined from the inscription applied by the manufacturer on the body of the device. It is a certain alphanumeric code, which is quite simple to decipher. So, the most common are socles of type E27. Here the letter "E" denotes a screw type (derived from "Edison"), and the number "27" indicates the distance between the two outer opposite points of the thread. A slightly smaller size of E14, better known as the "minion", is often used in table lamps. And quite "kids" - E12 and E10 - are used in lighting fixtures for special purposes. Large industrial lamps are supplied with E40-type socles. Here is such a significant spread in thread diameters. But the plinths of fluorescent lamps, for example, are executed in a completely different way. For ease of installation and replacement, it was decided to replace the screw with pins. It is denoted, 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 designed in such a way that the pin pins are fixed with special pressure plates while turning the lamp, ensuring reliable electrical contact. The second name for this modification of the socle is bayonet. Also, there is a directly "pin" solution (modification "G"), when the pins are directly inserted into the chuck without requiring rotation. This is often used in spotlights. Thus, the cap is an entire system designed to fix the lamp and transmit electric current to its internal circuits.