What is a cap?
A bulb cap is the part of a light bulb, in which a bulb and an illuminating body are inserted. This bulb cap then fits into a bulb socket in a light and transmits electricity from the mains electricity to a light bulb. What that means is that each light is equipped with a specific bulb socket and for this bulb socket a suitable light bulb has to be chosen, more precisely a light bulb with a suitable bulb cap/screw cap has to be chosen.
LED technology as an effective alternative
In today’s world, LED technology is the most modern and most effective. This technology is significantly more energy-saving, has a long lifetime and replaces all existing light sources which means, that all standard light bulbs with all types of a bulb cap are also available as LED light bulbs. You can even choose a shape and a size of a bulb.
Power supply/input power of a light source
The light sources powered by 230 V AC – from the mains
Nowadays 230 V LED bulbs are most often used as a replacement for standard light bulbs and spotlights with a voltage of 230 V. You can simply change these bulbs, no need to purchase any other components.
The light sources powered by 12 V – for these bulbs and lights you need in most of the cases a power supply, which converts the voltage from 230 V to 12 V (some LED lights are already equipped with an integrated power supply). Remember, that for different types of light bulbs you need a suitable type of a power supply/transformer.
Types of caps
Screw cap (a cap with a screw)
Most commonly used are the bulb caps with a screw and these are divided based on the size. Each size is used in a different type of a light source and each is suitable for a different use. The number indicates a diameter of a bulb cap in millimetres.
E27
Standard large screw E27 is most common and most used. It is also known as “Edison screw” – hence the letter E, the number 27 indicates the diameter in millimetres.
LED light bulbs, halogen bulbs, energy-saving bulbs, standard tungsten bulbs as well as vacuum tubes are equipped with this cap. The lights with such bulb caps are suitable as the main lighting in rooms, garages, hallways, cellars as well as for outdoor use. For this bulb there are also unconventional decorative light bulbs. The vast majority of bulbs with a bulb cap E27 are intended for voltage of 230 V, but we can also find some low-voltage bulbs for 24 V.
E14
En standard lille skrue med en diameter 14 mm er den næstmest almindelige. Det dagligdags udtryk for denne skrue er "lille Edison-skrue"..
The bulbs E14 have a lower input power (25 W or 40 W) and are usually intended for designer and decorative lights, lamps and chandelier, to kitchen extractor hood etc. The shape of bulbs is a candle or a drop. The special application of light bulbs with a bulb cap E14 are directional, so-called reflector bulbs. These bulbs are made as LED bulbs as well as standard bulbs. Also very often compact energy-saving fluorescent tubes are equipped with a cap E14. These compact energy-saving fluorescent tubes replace standard light bulbs.
Less used caps with a screw, which are rather used at technical or industrial applications of light bulbs.
E40 – “Goliath”
This cap is the biggest from screw caps with a diameter 40 millimetres.
This cap is intended for very powerful applications of light bulbs. In the past this cap was used for light sources with an output up to 2000 W, nowadays are used mainly for vacuum tubes with an output up to 400 W. Thanks to its properties these caps are mainly used at special light bulbs intended especially for industrial and outdoor lighting.
E10 – “Miniature Edison Screw“
The cap for low-voltage applications of light bulbs. The cap E10 is commonly used in flashlights or in Christmas chains.
The cap for low-voltage applications of light bulbs. The cap E10 is commonly used in flashlights or in Christmas chains.
Bayonet caps
Bayonet caps are smooth cylinder-shaped with two opposite pins. They fit into “L”-shaped openings in a bulb socket. There is a sprung touch at the bottom of a socket. A light source is inserted in a socket by pushing against a spring and is secured by a rotation. Thanks to using a spring, bayonet connection is resistant against shocks.
B22
These caps are made as LED bulbs however, they are also used in energy-saving bulbs and halogen bulbs. They are intended for a voltage of 230 V.
B22d
At our eStore you can find LED bulbs with this cap, which are suitable for example for outdoor decorations.
At our eStore you can find LED bulbs with this cap, which are suitable for example for outdoor decorations.
GU10
A letter G is the first letter from an English word globular, a letter U stands for the shape of a bulb and number 10 indicates a spacing of pins in millimetres.
GU10 is a cap with two symmetrical pins of a 5 millimetres diameter and with a spacing of 10 millimetres. Originally this cap was intended for halogen light sources with directional lighting. Nowadays they are being replaced by LED bulbs GU10, which are available with three different color tones and in 4 different groups sorted by output power (wattage).
This cap is very common, is intended for a voltage of 230 V and is typical for light bulbs used in spotlights. Some types of LED bulbs with this cap are dimmable.
Pin caps
Commonly used at fluorescent tubes and compact
fluorescent tubes. These fluorescent tubes are sometimes termed as one-cap. From the plastic end of the cap, two or four pins stick out. The bulbs with two pins have an integrated starter and for an operation they require an external choke. The bulbs with four pins from the cap require external ballast. It may be conventional, composed of a starter and a choke or electronic. The shapes of a bulb cap and a socket are normalized. These caps are also sometimes used for some halogen bulbs.
G13
These bulb caps are used for fluorescent tubes type T8. It is an older type of fluorescent tubes, which have been used for decades. The typical characteristic of these caps is a wide diameter – 26 mm and good color rendering, which usually ranges from 80 – 90 Ra, and at the top-notch models even above 90 Ra. The fluorescent lights with a cap G13 are switched on through an Electromagnetic ballast. Nowadays also LED tubes T8 are produced, which are connected directly to AC 230 V and unlike standard fluorescent tubes, LED tubes T8 don’t need a started nor a choke. Electromagnetic ballast is built-in directly in a tube. These caps are suitable for household lighting, garages, workshops as well as public and industrial buildings.
G5
This cap is intended for a voltage of 230 V AC and is used in modern fluorescent tubes type T5, which gradually replace an older type T8. The advantage of fluorescent tubes T5 is a smaller size and a diameter, which is only 16 mm. These fluorescent tubes (T5) are suitable for lighting of public spaces, supermarkets and offices. They are also often used in fishkeeping. T5 LED fluorescent tubes are also available which, like above-mentioned fluorescent tubes T8, don’t need ballasts.
2G7
Four pins plug-in energy-saving fluorescent tubes/bulbs.
Four pins plug-in energy-saving fluorescent tubes/bulbs.
S14s
You can find fluorescent lights and tubes with this cap in our eStore, available are also LED fluorescent lights and tubes with a cap S14s.
Other types of commonly used caps (plug-in)
G4
Two-pin cap (longer pins, like needle pins) with a spacing of pins 4 mm, which is inserted into a light. This cap is used in halogen bulbs as well as in LED bulbs with a voltage of 12 V, which are suitable for lighting bathroom cabinets, bookcases, mirrors, kitchen units, low lowered ceilings as well as bars.
G9
This cap is intended for a voltage of 230 V and is composed of two flat pins with a spacing 9 mm. The bulb is simply inserted. This cap was originally intended for halogen lighting however, nowadays it is used also for LED bulbs G9. This cap is also widely used in modern lights, where this cap is very often applied. This cap can be also found in ceiling and wall lights, small spotlights and desk lamps.
MR16/GU5,3
This cap is termed as MR16 or GU5,3 has two pins resembling of thorns with a spacing 5,3 mm without an ending, the bulb only needs to be inserted. MR is an acronym of English collocation “multifaceted reflector”. Is intended for a voltage of 12 V, but as well as for standard mains voltage. The cap is used in spotlights (built-in, wall, ceiling). The light bulbs with a cap MR16 are suitable for spaces with increased humidity thus, they are used in bathrooms, shower enclosures, swimming pools, kitchens etc. Also LED bulbs and halogen bulbs with this cap are available.
GX53
A special cap for flat round light bulbs or reflector (directional) bulbs. Suitable for both indoor and outdoor use.
A special cap for flat round light bulbs or reflector (directional) bulbs. Suitable for both indoor and outdoor use.
Finally, let’s recap the most common types of caps and their use in LED design:
LED light bulbs
E27
E14
G4
G9
LED spotlights
GU10
MR16/GU5,3
LED fluorescent tubes
G13(T8)
G5(T5)
If you need further assistance with anything, don’t hesitate to contact our technical support here.
Basic types of caps
Paulina
