Ama-Photodiode, aziwa nangokuthi ama-photocell, yizitholi zikagesi eziguqula ukukhanya kube amandla kagesi.Zisetshenziselwa izinhlelo zokusebenza eziningi ezihlanganisa inzwa yokukhanya, ama-optical switch, kanye ne-digital imaging.Ama-Photodiodes ahlanganisa ukuhlangana kwe-semiconductor ekhipha ama-electron lapho evezwe ekukhanyeni.Umsinga abawukhiqizayo ulingana nobukhulu bokukhanya, futhi ungasetshenziswa ukuthola ubukhona bokukhanya noma ukulinganisa ubukhulu bakho.