OP550, OP552, OP555, OP750, OP755, OP770 and OP775 series consists of a NPN silicon phototransistor molded in an epoxy package with a wide receiving angle that provides rela vely even recep on over a large area. The OP750, OP755, OP770 and OP775 have addi onal circuitry to enhance the opera on of t.