Slotted optical switches (also called opto switches) are devices that provide status indications (on or off) when light beams are interrupted in various types of instruments, systems and equipment.
The switches contain phototransistors, which are illuminated by infrared light from the LEDs. The illumination causes the phototransistors to conduct. If objects are then placed into the slots between the transistors and the LEDs, the interruption of the light beams causes the transistors to switch off.
Optical slotted switches may also house rotating discs with holes around the rims. These holes spin within the light paths of the switches to create on and off pulses and direct the speed of the spinning discs.
Slotted optical switches are used in assembly line production systems, machine automation and machine safety indicators.
The switches are standard in computer peripherals like printers, where the projection images get interrupted when they reach the end of their travel.
Slotted optical switches are classified by their output mechanisms (buffers, inverters, interrupters), mounting types (through hole, panel, surface) and the number of pins located on the switches.