ExpEYES

Imagine a circular disc with a dot painted on it, towards the edge. If you rotate the disc, say 50 time per second, the dot will appear as a circular ring. This is because we see it at different positions during the rotation. Each rotation takes 20 milli seconds. Suppose we illuminate it using a pulsed light source that glows for a millisecond n every 20 mS. The dot will be illuminated only when it is at a particular angle. To our eyes it will appear stationary.

• Connect the Motor from PV1 to ground
• Set PV1 to 1 volts
• Connect a white LED from SQ1 to ground
• Adjust SQ1 frequency so that the motor appears stationary. The dots on the motor pulley will become stationary.

When the frequencies are very close, the motor will appear to rotate at a frequency that is the difference in the actual frequency of rotation and the frequency of illuminating light pulse.