It is placed on the dashboard and it shows the "engine spins", that is to say, the rotation speed of the engine. It varies depending on how much the driver is pressing on the accelerator, no matter whether the car is moving or not. Through the transmission, the acceleration will be linked to the wheels, and this will allow the car to advance.
Notice one day that when I turn on my head lights my radio goes out turn lights off and radio works then the next day my speedometers and rpm gauge stop workingnow the engine light is on but the car is still running