A tachometer simply measures the rotational speed of a shaft, wheel, pulley or a motor. This is a simple concept that can be difficult to accomplish, especially in an engine or confined space. Tachometers have developed into highly accurate, compact devices. Some models even feature laser or photo reading technology which offers non-contact readings and can be used on extremely fast rotations without worrying about damage or injury.
Tachometers are found in vehicles, generators, motors, bicycles and other rotating devices. They are vital to the functioning of engines, generators, airplanes and other devices dependant on sustaining a certain rotational speed. Tachometers have traditionally been analog devices displayed by a pointer on a dial but are now migrating toward digital displays which are more accurate and easier to read.