( ( ( ( ( ( Its ( copper coil ) ) ( of ( wire ( in ( the transponder ) ) ) ) ) , ) ( when ( moved ( through ( a ( magnetic field ) ) ) ) ) ) , ) ( ( produces ( ( electrical current ) ( that ( energizes it ) ) ) ) . ) )
(ROOT (S (NP (NP (PRP$ Its) (NN copper) (NN coil)) (PP (IN of) (NP (NP (NN wire)) (PP (IN in) (NP (DT the) (NN transponder))))) (, ,) (SBAR (WHADVP (WRB when)) (S (VP (VBD moved) (PP (IN through) (NP (DT a) (JJ magnetic) (NN field)))))) (, ,)) (VP (VBZ produces) (NP (NP (JJ electrical) (NN current)) (SBAR (WHNP (WDT that)) (S (VP (VBZ energizes) (NP (PRP it))))))) (. .)))
Its copper coil of wire in the transponder, when moved through a magnetic field, produces electrical current that energizes it.
(ROOT (S (NP (NNP Alternative) (JJ current)) (VP (VBZ is) (VP (VBN produced) (SBAR (WHADVP (WRB when)) (S (NP (DT a) (NN magnet) (CC or) (NN coil)) (VP (VBZ moves) (ADVP (RB back) (CC and) (RB forth)) (ADVP (RB repeatedly))))))) (. .)))