# Stroboscope

Stroboscope Instrument that allows you to visualize an object that is rotating as if it were stationary or rotating very slowly.

## Summary

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• 1 Description
• 2 Use
• 3 Scope
• 4 Current use
• 5 Sources

## Description

The stroboscope is an instrument invented by the Austrian mathematician and inventor Simon von Stampfer around 1829 , which allows you to visualize an object that is rotating as if it were stationary or rotating very slowly.

This principle is used for the study of rotating or vibrating objects such as machine parts and vibrating cords. It was developed around the same time that Belgian physicist Joseph Plateau was unveiling his phenachistiscope.

## Use

Allows you to turn lights on and off, in a given time, the number of times you want. This device is widely used in nightclubs, on airplanes and in film production to give the feeling of fast movements.

In essence, a stroboscope is equipped with a lamp, normally of the xenon gas discharge type, similar to those used in photography flashes, with the difference that instead of a flash, it emits a series of consecutive ones and with a frequency adjustable. If we have an object that is rotating at N revolutions per minute and we regulate the frequency of the stroboscope at N flashes per minute and illuminate the rotating object with it, this, being always illuminated in the same position, will appear to the view as immobile.

## Scope

A periodically adjusted strobe light may appear to freeze cyclical motion.

If the frequency of the flashes does not exactly coincide with that of rotation, but is very close to it, we will see the object move slowly, forward or backward depending on whether the strobe flash frequency is, respectively, lower or higher than the turn.

A well-known application of this instrument was adjusting the speed of older vinyl record players. These devices had marks drawn on the edge of the turntable, marks that were illuminated by the light of a gaseous discharge lamp, in this case neon, fed by the alternating current of the 50 Hz or 60 Hz electrical network ( in most American countries).

As the number of marks was calculated so that, with the correct speed of rotation, one mark passed each second in front of the neon lamp, the marks appeared immobile when the speed was indeed correct. Most turntables had two bands for an identical spin speed, to adjust this well outside with 50 or 60 Hz AC.

## Current usage

Today the stroboscope is still used to verify the speed of rotation of machines and motors of various kinds, without the need for any electrical or mechanical coupling.

Conversely, if various images corresponding to different phases of the movement of an object are pasted on a rotating disk and illuminated with the stroboscope in such a way that a flash occurs each time an image passes in front of the image, leaving the plate without lighting during the space between one image and another, the result will be that the object will be observed in motion. Based on this principle, called the strobe effect, cartoon films are based.