What is Photodiode?
[[File:USSR photodiodes.JPG|thumb|300px|{{center|Photodiodes}}]] A '''photodiode''' is a light sensitive [[semiconductor]]. It is a type of [[photodetector]] capable of changing (or converting) light into either [[electric current|current]] or [[voltage]], depending upon its connections.<ref>{{GoldBookRef|title=Photodiode|file=P04598}}</ref> It is a [[diode]] and wired with reverse [[biasing]] so that when in the dark, only a small amount of current, known as dark current, will flow. When in the light, a current known as photocurrent flows through the diode. Photodiodes may contain [[Optics|optical]] [[filter]]s, built-in [[Lens (optics)|lenses]], and may have large or small [[surface area]]s. Photodiodes usually have a slower [[:en:wikt:response time|response time]] as its surface area increases. The common, traditional [[solar cell]] used to generate electric [[solar power]] is a large area photodiode. Photodiodes and [[:en:wikt:phototransistor|phototransistors]] look the same physically but have different functions.<ref>Cathleen Shamieh; Gordon McComb, ''Electronics For Dummies'' (Hoboken, NJ: Wiley Pub., 2009), p. 337</ref> It is based on a reversed bias circuit. ==References== {{Commonscat|Photodiodes}} {{Reflist}} [[Category:Electronics]] [[Category:Physics]] {{physics-stub}}