A supercharger is a device which is used to compress the intake air and in cars, it works the same way. In cars, it is used to increase the power and torque of the car.
Since, it may be clear to you that for an increased performance of any car there should be more intake of fuel into the combustion chamber and also for making use of this more fuel for burning, it requires more air too. So, this will eventually increase engine size which may not be a good idea. To overcome this problem, superchargers are used which compress the air (make its size small) and pushes into the combustion chamber. So, by adding supercharger which compresses air, there is no need for increasing engine size.
The supercharger is linked with the crankshaft which powers supercharger, this leads to a disadvantage of decreasing car efficiency but there will be a good increase in performance. Supercharge consists of two main gears namely – drive gear and compression gear. To compress air, it is essential that compression gear rotates faster than drive gear, so usually; compression gear is smaller in size than drive gear. All this consists of the main working of Superchargers.