After all transients died out, the steady induced angular velocity of the interior was picked up by the photocell and recorded.
A photocell's response to the light stimuli is shown below each set of traces.
A photocell's response to the light pulse is shown below each set of traces.
A photocell's response to the flash is shown below each set of traces.
A photocell sandwiches part of the disk and records its angular velocity.
In the projector the film is transported in such a way that the soundtrack passes between a light beam and a photocell.
When the disc is rotated, each ring varies the way in which a light beam affects a photocell.
The drawn waveforms pass over photocells, illuminated from above by a steady stream of light, to the right of the flat surface.
