What type of sensor transmits infrared light to a photocell?

The photoelectric beam sensor is designed to transmit infrared light to a photocell, which is used to detect interruptions in the infrared beam to trigger an alarm or notification. This type of sensor operates by sending a beam of infrared light from a transmitter to a receiver. When an object or person crosses the path of the beam, it interrupts the signal, signaling the presence of an intruder. This system is commonly employed in security applications because it can cover significant distances and provides a reliable means of detecting movement across an area.

While motion detectors also respond to movement, they don't specifically use infrared light directed towards a photocell in the same manner as a photoelectric beam sensor. Passive infrared sensors detect the heat emitted by objects, such as humans or animals, rather than transmitting light and functioning with a photocell. Magnetic sensors, on the other hand, typically work by detecting changes in magnetic fields, often used to secure doors and windows rather than utilizing infrared technology. Thus, the defining characteristic of the photoelectric beam sensor is its use of infrared light to trigger a photocell, making it the correct answer.