In both cases, a spinning or oscillating disk with a narrow radial slot either allowed the object to be viewed at regular intervals or permitted light to illuminate it at successive instants, thus exposing it at precisely the times it reached a given point in its motion.
Modern ones use a gas-filled discharge lamp to create the necessary effect. Early ones utilized either intermittent vision or interrupted light. In both cases, a spinning or oscillating disk with a narrow radial slot either allowed the object to be viewed at regular intervals or permitted light to illuminate it at successive instants, thus exposing it at precisely the times it reached a given point in its motion. FTP, name this device that allows the study of the motion of an object or determines its rotary speed or vibration frequency.
Modern ones use a gas-filled discharge lamp to create the necessary effect.
{stroboscope}