s are sensitive to light
. Photodiodes are just doped
so that they are more sensitive. When a photon
hits the pn junction
, it causes an electron
to jump the gap. Do this with enough photons and enough photodiodes, and you can run a pocket calculator
When you don't want to harness the photodiode for energy, but want to use it as a light detector, you should consider using the more sensitive phototransistor instead.