如图所示，\(A\)、\(B\)、\(C\)为三个相同的灯泡，\(a\)、\(b\)、\(c\)为与之串联的三个元件，\(E_{1}\)为直流电源，\(E_{2}\)为交流电源\(.\)当开关\(S\)接“\(1\)”时，\(A\)、\(B\)两灯均正常发光，\(C\)灯不亮\(.S\)接“\(2\)”时，\(A\)灯仍正常发光，\(B\)灯变暗，\(C\)灯常发光\(.\)由此可知，\(a\)元件应是 ______ \(b\)元件应是 ______ \(c\)元件应是 ______ ．