IR Photodiode is used to detect the light rays reflected from an IR LED. A photodiode is a reverse-biased PN junction diode. When a photodiode is exposed to light, electrical resistance across the diode decreases thereby increasing the reverse current. If the photodiode is not exposed to light, the resistance across the will be high .hence reverse current will be extremely small. This current is known as the dark current.

When light falls on the photodiode, electrons acquire sufficient energy to break the covalent bond. Thus free electrons and holes are created. These free electrons will increase the reverse current.IR transmitter LED will be emitting IR rays continuously since it’s connected in forward biased state. When an obstacle is present, IR rays from LED get reflected back and the IR receiver will capture these rays. Now the IR receiver will conduct, an active low output will be produced.

Package Includes:

1 x IR Sensor Module