Modern vehicles use many different kinds and sizes of lamps, also known in some places as light bulbs, or light globes.
Incandescent lamps
'Incandescent' lamps all consist of one or more filaments which heat up until they glow. The filament material doesn't burn because most of the air in the bulb has been replaced by inert gases that stop combustion occurring.
The power in watts is often marked on the lamp. The power in watts being consumed by the lamp is found by multiplying the voltage to the lamp by the current flowing through it.
Halogen lamps
Halogen lamps are filled with a halogen gas such as bromine or iodine. These have a much longer life, and are generally brighter and produce more light per unit of power consumed, but they are very hot in use. They are consequently manufactured from highly heat resistant materials and the bulbs must be handled carefully because they are sensitive and can be damaged even by residue from fingerprints.
Other lamp types
Conventional incandescent lamps are being replaced in many applications by other more efficient types of lights, such as fluorescent lights, high-intensity discharge (HID) lights, and light-emitting diodes (LED).
