Modulated light pulse generator - has apertured shutter disc rotating between light source and phototransistor

摘要

The modulated light pulse generator uses a light source connected to DC voltage and an apertured shutter disc rotated in front of the light source. The shutter disc is rotated via an AC electric motor having a dipolar stator magnetic circuit with an induction winding. The supply voltage for the light source is obtained from a supply coil around the magnetic circuit and by a rectifier bridge receiving the voltage induced in this coil as result of the magnetic flux. The modulated light pulses may fall on a phototransistor (40) supplied from the same DC voltage and providing a corresponding electrical pulse signal.