4. Stroboscopes

4.1 Measuring principle

Another device for measuring rotation speed is the stroboscope. The measuring principle consists in generating flashes whose frequency is equal to the rotational speed of the device whose speed is to be measured. When the two speeds are perfectly equal, the rotating system appears to be stationary.

A stroboscope's reference is a time base, which can be quartz-controlled for the most precise devices. Depending on the device, the minimum speed is between 30 and 100 rpm, while the maximum speed is around 10,000 rpm, with some devices reaching 18,000 rpm.