Number in set
Number of lamps included in delivery.
The headlight lamps (see “Purpose”) are paired and can be supplied either
one or
two at a time - the latter is ideal if you need to install or replace both lamps at once. Also, paired configurations can be found in models for auxiliary lighting, and sometimes such lamps are supplied in
sets of 10 or even 100 pieces - this can be useful, for example, for installing side lights on a bus or truck. But the dashboard lamps are sold exclusively one at a time.
Voltage
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.
Colour temperature
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.
Lifespan Tc
The maximum continuous lamp operation time. This indicator is quite approximate and the probability that the lamp will work during this period is approximately 1 in 3. This is due to the measurement technique: a control batch of lamps is used until 63.2% of them fail, the resulting time and indicated as "maximum service life". However, the Tc data compared to the B3 guaranteed life (see above) provides a good estimate of the overall lamp life and its ability to last beyond the guaranteed life.
