Tachometer

A tachometer is a sensor that measures the rotation speed of an object, for example a wheel or shaft. There are different methods to do so (for example, mechanical, optical, or magnetic). Most tachometers display the measurement in revolutions per minute.

Tachometer Media

A tachometer that can indicate up to 7000 RPM (left)
Cessna 172's G1000 tachometer (1,060 RPM) and engine hours (1736.7 hours)
A tachometer on a tractor, reading up to 3000 RPM, with the hour meter below it showing 772.9 hours. The mark at 2500 RPM is the engine speed required to run the power take-off at 540 RPM.

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