Phase measuring strobe


We needed to determine the phase of the motion of an actuator relative to the sinewave driving it. The following circuit detects the sinewave zero crossing, then produces a light flash some time later. The delay time at which the strobe shows the actuator crossing zero (when viewed under a dissecting scope), compared to the period of the sinewave, yields the phase.

The Circuit


The following image shows the yellow LED near the actuator sphere.