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August 12, 2017 18:07

The most common sockets lighting lamps

The main purpose of the cap - lock the bulb in a cartridge and the power supply from the power source.Also, this design provides sealing element inside the bulb when it is pumped with the air and creates a vacuum.Photo : standard screw base
Today, there are many sizes and types of caps lighting lamps, which we now discuss in more detail.
  • Marking
  • Feature
  • Exceptions
  • popular


most ancient type is threaded, which was invented by Thomas Edison in the late 19th century (the indexE).In addition, the following marking lamp base:

  • G - prong;
  • R - with external contact;
  • F - with one pin (a - a cylindrical, b - grooved, with - the special form);
  • B - pin;
  • S - soffit;
  • K - with cable connection;
  • P - focusing;
  • H - for xenon bulbs;
  • T - telephone;
  • W - current inputs are in the glass bulb.

draw your attention to the fact that, in addition to one of these letters can be put in charge of another: U, V or A, which means, respectively, for energy-saving lamps, with tapered end of any type of car.

further contains numerical marking showing the diameter of the cap, or the distance between two pins (in mm).After the figures may be indicated by the number of connections (flexible plates or pins).For this purpose, the letters s, d, t, q, p, which is 1, 2, 3, 4 or 5 contacts.

illustrative video tutorial on the size and classification of products
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Now a closer look at the main characteristics of all types of household light bulbs caps and their conditions of use


Screw (E). Despite the fact that he appeared very first almost half a century ago, its popularity this type has not lost to this day.This is a simple and user-friendly design, which allows you to twist the flask in seconds.Now these types of caps can be installed in all kinds of light bulbs: LED, halogen, fluorescent, and, of course, the bulbs.As for the types of threaded caps, they may have the following diameters according to GOST: 5mm (E5), 10 mm (E10), 12 mm (E12), 14 mm (E14, EP), 17 mm (E17), 26 mm (E26), 27 mm (E27, normal), 40 mm (E40).At home, usually less than E14 is not used.

pin (G). Typically used in halogen, fluorescent and LED light sources.The design shown pins, which are also easily and quickly connected to the network.A variety of products is the distance between the pins, as well as their amounts.For example, G4 type means that the distance is 4 mm and G5.3, respectively, 5.3 mm.The disadvantage of this design is that the eye-novice electrician will be difficult to determine what size cap to buy (for example, when the fluorescent lamp fails), so you need to go to the store with a broken example.Pins for connection to the network

with recessed contact. This type of lamp base is used in lighting and tubular quartz halogen light sources, which have a high temperature heat and power.

Recessed contacts with ends

draw your attention to the fact that the number (eg, 118) may be present in the labeling of these products.It means the total length of the entire product.

soffit (S). This type is most often used when installing lighting in the bathroom, as well as to illuminate the mirrors.Designation S6 or S8,5 means that the diameter of the housing 6 (8.5) mm.

size C6

Bayonet (B). This type of action is a principle similar threaded.The only difference is that the need to thread the threaded connection, in this case, the two pins set opposite one another on the outer diameter of the cap.This design simplifies lamp connection to the network.Basically, the application area is automotive lighting.Marking is performed as follows: BA - pins are symmetrical, BAZ - one of the pins and radially offset adjustment, BAY - offset occurred only radially.The number indicates the diameter of the shell in mm.

Light bulb with a pin

Focusing (P). Its design is represented by a lens through which takes place the focus of the luminous flux (the photo shows an unusual shape).Most often, this type of cap is used in automotive lighting, as well as floodlights and street lamps.Digital displays markings diameter at a location where the lamp is used, or the size of the flange, which focuses the light beam.

focusing lens

phone (T). can be used for lighting appliances in the car, as well as for the signal lights in the automatic control boards.Marking digital displays contact plate width (mm).

As for the rest, they are used very rarely, and she may not even mark.In this case, it indicates the type of the lamp illuminated, which has already been determined and the size and type of socket.


As we have said, some of the types of lamp cap may be missing markings, which instead will refer only to the light source.In this case, to determine the standard size is possible only according to the markings on the product.

To your attention the basic labeling:

  • MR16 - Halogen lamp having a reflector.It is usually installed prong base (Code G).
  • R50 - reflector, with thread-lock in the ceiling of (E).
  • 2D - LED (CFL) having pins for connection.

I would also like to pay attention to linear fluorescent lamps.The diameter of the tube determines the size of the cap.There tubular bulb having various T5, T8, T12 and T15, respectively, in diameter: 1.59 cm; 2.54 cm;3.17 cm, 3.80 cm

lamp T5


For incandescent lamps the most popular are 2 types of screw caps: E14 (EP) and E27 (standard)..

Dimensions E14 and E17

prong (GU10 or G13) and a threaded view (E14 and E27) is used for spotlights.

Compare GU10, E27, E14

fluorescent lamp device may include these types of caps as G13, G23, G24, G53.

Halogen lamps are most commonly used G4 sizes, G9 and R7s (the latter option is set in the quartz lights.

Here you also got acquainted with existing types and sizes of caps lamps lighting. We hope!, that the information was available, and most importantly - useful
also read:

  • How to unscrew a broken light bulb socket
  • How to make LED lamp with his hands
  • How to conduct light in the house