Stroboscope

From ArticleWorld

A stroboscope is an instrument that is used to make a rotating or vibrating object appear stationary or slow moving through the use of flashing lights which intermittently illuminate it. The flashing frequency is adjusted until the object looks stationary and hence the rotation speed or the vibration frequency can be found out.

Simpler stroboscopes use intermittent vision instead of flashing lights. The moving object is exposed at a particular point of its motion at regular intervals through a rotating disc with evenly spaced holes. The disc's speed is adjusted until the moving object slows down and stops.

Modern electronic versions use electric gas-filled lamps known as discharge lamps that emit light when electricity is passed through them. These stroboscopes produce bright flashes of very short duration and at a very high speed. Flash rates range from a few hundred to hundreds of thousands flashes per minute. The duration of a flash is lesser than a thousandth of a second.

Applications

Stroboscopes are used in engineering to study stresses on moving objects in machines. They are also used to determine the rotational or vibrating speeds of machinery.

Stroboscopic disks are used in gramophone turntables to determine their speed. Bright flashing lights are used to make marks at the edge of the rotating platter appear stationary.

Other uses of stroboscopes include vehicular engines where they are used to set ignition timings, in medical examination of vocal cords and in capturing images of moving objects.