Stroboscope

In its simplest mechanical form, a stroboscope can be a rotating cylinder (or bowl with a raised edge) with evenly spaced holes or slots placed in the line of sight between the observer and the moving object.

These delays result in smearing and blurring of detail of objects partially illuminated during the warm-up and cool-down periods.

Yet when operated from an AC source they are mostly fast enough to cause audible hum (at double mains frequency) on optical audio playback such as on film projection.

Joseph Plateau of Belgium is generally credited with the invention of the stroboscope in 1832, when he used a disc with radial slits which he turned while viewing images on a separate rotating wheel.

There was an almost simultaneous and independent invention of the device by the Austrian Simon Ritter von Stampfer, which he named the "Stroboscope", and it is his term which is used today.

As well as having important applications for scientific research, the earliest inventions received immediate popular success as methods for producing moving pictures, and the principle was used for numerous toys.

In 1917, French engineer Etienne Oehmichen patented the first electric stroboscope,[1] building at the same time a camera capable of shooting 1,000 frames per second.

[2] General Radio Corporation then went on to produce this device in the form of their "Strobotac", an early example of a commercially successful stroboscope.

[3] Edgerton later used very short flashes of light as a means of producing still photographs of fast-moving objects, such as bullets in flight.

Flashing lamp strobes have also been adapted as a lighting effect for discotheques and night clubs where they give the impression of dancing in slow motion.

The strobe rate of these devices is typically not very precise or very fast, because entertainment applications do not usually require a high degree of performance.