Speedometer Gauges

Your dashboard instrument cluster organizes plenty of gauges, including a fuel level gauge, coolant temperature gauge, tachometer and, of course, a speedometer. Beyond a doubt, the latter one is the most prominent and important gauge found on your dashboard. It does a crucial job, indicating the speed of your vehicle in miles or kilometers per hour while you're driving. Depending on the make and model of your vehicle, it can be either mechanical or electronic. They differ in design and construction, yet serve the same purpose of informing a driver how fast his or her vehicle is running.

Today, it's hard to imagine a car, truck or motorcycle without a speedometer, although, it came as an option on most vehicles at the dawn of the automotive industry. The first modern mechanical speedometer was built in the late 1920s and had been the only type of speedometers found in vehicles till the 1990s. A mechanical speedometer features a printed dial and a needle pointed at a specific number which corresponds to the speed of a vehicle. The needle is moved by electromagnetism powered by the rotation of a magnet inside the gauge that is caused by the rotation of the cable that connects the speedometer and driveshaft.

Mechanical speedometers dominated in the automotive market for almost 70 years. However, with the development of digital technologies, they had to cede leadership to electronic speedometers in the 1990s. While doing the same job as their analog counterparts, electronic speedometers perform in a completely different way. Their principle of operation is based on magnetic sensors that read the quantity and amount of electric current caused by tiny magnets attached to the rotating driveshaft and positioned nearby the sensors. A computer converts this pulsation into a speed and shows it on an LCD display. Instead of a digital display, some electronic speedometers can be equipped with an analog dial. In that case, the needle is moved by a computer-controlled stepper motor.