You will notice that the dashboard of a car has many different gauges. Each gauge serves a specific purpose and many indicate information about the engine compartment. The fuel gauge, speedometer, and tachometer are the most commonly found gauges in a car.
These gauges are vital for any car because without them you wouldn't know what is going on inside. Some people add other gauges to their dashboard instrument cluster if they are passionate about cars, such as the water temperature gauge and oil temperature gauges, exhaust gas temperature gauges, voltage gauges, etc.
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In older vehicles, the speedometer has two parts: speedometer cable and speedometer gauge. As speed increases, the speedometer gauge moves the needle in a circular motion. The speedometer drive gear transmits the speedometer cable's circular motion to the gauge. The cable is no longer necessary for the latest cars with electronic fuel injection.
They use a speedometer sensor that converts the circular motion signal from a speedometer drive gear into an electric signal. This signal is then read by the engine computer, which then sends it to the speedometer gauge.
The needle moves up or down according to the electrical pulses received. The speedometer can give a very accurate reading of the speed in miles per hour and kilometers per hour. The accuracy of the speedometer can be affected by the size of the tire. You can even search online for more information about cluster instrument repair.