Comparison ALed 7440 W21W White 2pcs vs Osram LEDriving Standard WR21W 7705R-02B

The type of base used in the lamp.

The base is the contact part of the lamp, which is fixed in the socket and is responsible for fixation, electrical connection and the possibility of safe removal. Thus, the type of base directly determines compatibility with a particular cartridge. However, in addition to this, there is also such a parameter as the base of the base. It determines primarily the contact configuration used on a particular base. And in our paragraph it is written as the second value.

In lamps for different purposes (see above), the set of bases used is very different. So, for the head light the following options are used: D1S, D1R, D2S, D2R, D3S, D3R, D4S, D4R, H1, H2, H3, H4, H7, H8, H9, H10, H11, H13, H15, H16, H27W /1, H27W/2, HB1, HB3, HB4, HB5, HIR2, HS1, M5, R2. For markers and other similar lights, in particular, C5W, C10W, C15W, H21W, H6W, P21W, PY21W, P21/4W, P21/5W, P27/7W, PR21W, R5W, R10W, T4W, W5W, WY5W, W16W are used , W21W, WY21W, W21/5W.

If desired, you can find a detailed explanation of each designation in special sources.

The operating voltage of the lamp.

In different types of equipment, the voltage of on-board networks is also different. Therefore, car lamps for passenger cars are designed for a voltage of 12 V, and car lamps for trucks(and other similar equipment, such as buses) are designed for 24 V. However, there are more specific options:

— 12/24 V. Lamps with the possibility of using in both types of on-board networks — both cars and trucks. Such versatility is found mainly among LED models, as well as in some varieties of xenon (see "Type"): these types of lamps are equipped with control circuits in which automatic adjustment to the voltage of the on-board network can be provided.

— 85 V. Value found in models with a xenon principle of operation (see "Type"). In this case, it means the voltage supplied to the lamp from the ignition unit (see below); the ignition unit itself is connected to the on-board network and is usually designed for 12 V. Data on the operating voltage of the lamp itself may be needed if you need to separately select the ignition unit for it.

— 40 V. Another option for increased voltage in xenon lamps; the meaning is completely similar to the 85 V described above, but it is much less common.

The angle of illumination provided by the LED car lamp (see “Type”). This parameter, as a rule, is selected by the manufacturer taking into account the purpose (see above) and other features of the lamp’s use.

Models for headlights (see “Purpose”) usually have fairly large coverage angles - from 270° to 360°(the latter cover almost the entire sphere, with the exception of the space behind the base). This is necessary to work effectively with headlight reflectors. Theoretically, the larger the illumination angle, the more efficiently the reflector area is used and the higher the actual brightness; however, in practice this difference is not so noticeable, and much depends on the specific configuration of the reflectors. A specific type of LED headlight lamps are models with an illumination angle of about 60°, in which the concentration of the light beam is ensured by the built-in reflectors of the lamp itself.

In turn, in auxiliary lighting, the angles are selected for the specific specialization of the lamp and are usually at least 120°(maximum - the same 360°).

Luminous flux produced by a car lamp; for dual-mode models like bi-xenon (see “Type”), the value at maximum brightness is indicated.

This parameter characterizes the actual brightness and efficiency of the lamp; it can be used to directly evaluate and compare different models, regardless of their type and power consumption (but only at the same color temperature - see below for more details). The brightest are headlight lamps (see “Purpose”), in them this indicator can exceed 4000 lm and vary noticeably from model to model. Therefore, when choosing such a lamp, you should pay special attention to the characteristics of the luminous flux. It should be borne in mind that too bright headlights are just as undesirable as too dim ones: high brightness creates not only the risk of dazzling for oncoming cars, but also discomfort for the driver himself. Optimal luminous flux values can be indicated in the documents for the car or for the headlight itself; if such data is not available, you can turn to other special sources.

As for other types of lamps, in models for auxiliary lighting the luminous flux is up to 800 lm, and in lamps for the instrument panel - up to 55 lm. Moreover, in both cases, the brightness is selected by the manufacturer taking into account the specific specialization and location of the lamp, so in such models this parameter is not a key one.

The colour temperature of the light emitted by the lamp. The overall colour of the glow depends on this indicator; and note that the higher the colour temperature, the more “cold” the light looks, the closer it is to blue and blue. Traditional incandescent bulbs produce warm light at 2500-3000K, 3000-3500K can be described as "slightly warmer than neutral", neutral white corresponds to temperatures of 3700-4500K, higher values correspond to cooler shades, and temperatures over 5000K characteristic of lamps with a blue (blue) colour of the glow.

Note that in this case the colour temperature of the lamp itself (more precisely, its filament or LED element) is indicated, and not the actual shade of the glow that it will give out; for the difference between these indicators, see "Glow colour". Also note here that it is possible to evaluate the shade of light by colour temperature in headlight lamps (see "Intended use"), for which the white colour of the glow is claimed. At the same time, this indicator has a very practical meaning: the warm colour of the light is considered optimal in wet weather, the neutral one gives the highest visible brightness, all other things being equal, and the cold “long-range” one can be subjectively pleasant for some drivers, and can also be used as an element of external tuning.

Standard lamp colour.

Note that in this case it is not meant the own shade produced by the lamp (see "Colour temperature"), but the light that will be obtained "in the end" during normal use of the lamp. For example, in auxiliary models (see "Appointment"), designed for brake lights, the colour of the glow is usually indicated as red — this is the standard colour for "stops". In this case, the lamp itself can have a colour temperature of the order of 4000 K (neutral white). Similarly, models used in fog lamps may be yellow, those used in turn signals may also be orange, and so on.

If we talk about the head light, then it is most often made white, and in such models you can determine the shade by colour temperature (see above). If a different colour is indicated in the characteristics of the “head” lamp, this most likely means that it has a coloured bulb, and the light emitted by the headlights will have the same shade. Note that we are talking about a shade, and not about a full-fledged light: for example, purple lamps will illuminate the surroundings with white light with a slight bias towards cold colours. At the same time, such lamps themselves will look exactly purple. Such features are useful primarily for external tuning of cars.