Editing PIN diode (section)

== Operation ==
A PIN diode operates under what is known as '''high-level injection'''. In other words, the intrinsic "i" region is flooded with charge carriers from the "p" and "n" regions.  Its function can be likened to filling up a water bucket with a hole on the side.  Once the water reaches the hole's level it will begin to pour out. Similarly, the diode will conduct current once the flooded electrons and holes reach an equilibrium point, where the number of electrons is equal to the number of holes in the intrinsic region.

When the diode is [[p–n diode#Forward bias|forward biased]], the injected carrier concentration is typically several orders of magnitude higher than the intrinsic carrier concentration. Due to this high level injection, which in turn is due to the [[depletion region|depletion process]], the electric field extends deeply (almost the entire length) into the region. This electric field helps in speeding up of the transport of charge carriers from the P to the N region, which results in faster operation of the diode, making it a suitable device for high-frequency operation.{{Cn|date=July 2022}}