You may know how to drive or you are just like me who always tag along as side kick, but there is one part of automobile that is voluntary known to each one of us “Speedometer”. You may not be driving but one step on accelerator by the driver and you are squirming on your seat just as the needle on the meter. Ha!We have never really thought how does a needle move on the meter? What makes the number change on odometer? We look at speedometer but never really notice it. But not anymore join me in this insight to learn all about speedometer. Let’s understand in depth all about it.