3-1.BASIC STROBOSCOPE OPERATION.
3.1.1 WHAT IS A STROBOSCOPE
A stroboscope is a source of flashing light that can be synchronized
with any fast, repetitive motion so that a rapidly moving device seems to
stand still, or to move slowly.
To illustrate this principle, consider the following example:
Assume a white disc, with a single black dot, mounted on
the shaft of an 1800 -rpm motor.
When the disc is rotating at 1800 rpm, it is impossible for
the human eye to distinguish a single image and the dot
will appear to be a blurred continuous circle.
When illuminated by the flashing stroboscope light, syn-
chronized to flash once every revolution of the disc (when
the dot is at 3 o`clock, for example), the dot will be seen
at this position and only at this position at a rate of
1800 times each minute. Thus, the dot will appear to
"freeze" or stand still.