Difference between H4 and H7
Some vehicles have H4 bulbs in the headlights. Newer vehicles are mostly equipped with H7 lamps. But there are big differences between the light sources. However, these are relatively easy to explain.
Newer cars are usually already equipped with H7 lamps. However, that does not mean that such light bulbs are a further development of H4 lamps. There is a purely technical difference between these two light sources. Each version has both advantages and disadvantages.
This is how H4 lamps work
- H4 lamps are so-called bilux lamps. That means there are two filaments in one lamp. One is for the low beam and the other is for the high beam.
- When the low beam is switched on, a filament lights up and illuminates an overlying reflector. As a result, the light cone is thrown directly in front of the vehicle.
- When the high beam is switched on, the second filament is activated, which illuminates a reflector located at the rear. This throws the light cone far forward.
- This design shows a big difference to an H7 lamp. These lamps only have one filament.
An H7 lamp is a halogen lamp that is installed in the headlights of some cars ...
The difference between H7 and H4 lamps
- An H7 lamp is slightly smaller than an H4 lamp. However, since there is only a single filament in such a lamp, two lamps are required in each headlight.
- This means that a light bulb is mounted in a special reflector that illuminates the area in front of the vehicle when the low beam is switched on. The second lamp is switched on as soon as the driver switches on the high beam.
- So the difference is that two lamps are required for each headlight. But this also has the advantage that when the high beam is switched on, the area immediately in front of the car is well lit.
The only disadvantage of H7 lamps is that the headlights have to be much larger than the headlights for H4 lamps. Of course, this difference also affects the appearance of the front of the vehicle.
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