Speedometer how does it work

Now at the other end of the wire inside the speedometer cable is a magnet. That magnet sits inside something called a drag cup, which is made of a non-magnetic metal, usually aluminum. The magnet spins as the wire rotates, creating a magnetic field that forces the drag cup to turn in the same direction.

Attached to the drag cup is a spindle that connects to the pointer on your speedometer. A spiral spring on the spindle serves to counter the rotation of the drag cup. If you accelerate, the increased magnetic field moves the drag cup further around; as you slow down, the spring tugs the pointer back.

The whole system is calibrated so that the pointer indicates the proper speed. When you stop moving altogether, the spring pulls the pointer all the way to zero. Digital speedometers are a little different. A car with a digital speedometer uses a speed sensor, which usually consists of a magnet surrounded by a wire coil, quite like the pickup on an electric guitar. The sensor is mounted directly next to a gear on the transmission, and as the gear spins, its teeth whiz by, interrupting the magnetic field on the sensor.

The process is similar to the way a vibrating string activates a guitar pickup. The movement of the gear produces an electrical current that is directly proportional to the rotation speed of the gear. Mobile Newsletter chat avatar.

Mobile Newsletter chat subscribe. By: William Harris. Photo courtesy of Dreamstime. Cite This! Print Citation. The speedometer is the device in a vehicle that captures the speed and displays that data to the driver through the dashboard of the vehicle. There are several types of speedometers that work in various ways. They all measure how quickly the wheels rotate. Another component similar to the speedometer is the odometer. The odometer captures how far the vehicle has traveled.

The speedometer is part of the instrument cluster on your vehicle which displays important vehicle statistics such as speed, miles traveled, temperature of the vehicle, and fuel levels. The instrument cluster also is where you will find warning lights for your car. The speedometer has two separate semicircles which contain a set of numbers. The smaller semi circle shows numbers in kilometers and the exterior semi circle typically displays figures in miles.

As the hand of the speedometer sweeps through the circles, where it sits is the current speed of the vehicle. Car repairs can be absurdly expensive, and you can expect those unexpected repairs before too long no matter what vehicle you drive. A vehicle service contract from Protect My Car can help cover the cost of these excessive repairs. When you walk into the repair shop with a coverage plan from PMC, you can rest assured that you will never pay for these repairs listed here. If it does, just fill out the form below for a free quote, and see how great it can be to never have to pay for car repairs ever again.

Protect My Car offers multiple levels of extended coverage for Chevrolet vehicles. The chart below outlines what those levels cover and how much the deductible will cost. How Does A Speedometer Work? Facebook 0 Tweet 0 LinkedIn 0. Our goal here at Protect My Car is to eliminate your worry of being financially responsible for an expensive mechanical breakdown.