GDK-1 type anti-exposure electric controller circuit

The GDK-1 explosion-proof photoelectric controller circuit is shown in Figure 6-47. It is mainly used in coal mines, chemical industry, metallurgy, mining and other
departments as photoelectric automatic control, automatic counting, safety protection, non-contact switch, etc. It can effectively control the distance of 6m in low illumination environment and without
strong light source directly receiving the lens of the controller.
    The light-emitting head is equipped with a 6.3V, 2.5W instrument bulb, and the front lens holder is equipped with
a biconvex lens with a diameter of 30mm and a focal length of f = 44.275mm. The light-emitting head and the receiving controller are installed on both sides of the object under test. When the object to be measured is an opaque object
, the parallel beam emitted by the light-emitting head cannot enter the receiving controller. When the phototransistor VTI does not receive light,
the relay KA closes. If the beam is not blocked by the detection object, KA is released.