( ( Repeat ( ( ( moving coils ) and ) ( ( reading ( ( the ( magnetic ( field values ) ) ) ( -LRB- ( ( ( ( fig 2c ) , ) 2d ) -RRB- ) ) ) ) ( until ( the sensor ) ) ) ) ) ( ( touches ( the coil ) ) . ) )
(ROOT (S (NP (NP (NN Repeat)) (VP (VP (VBG moving) (NP (NNS coils))) (CC and) (VP (VBG reading) (NP (NP (DT the) (JJ magnetic) (NN field) (NNS values)) (PRN (-LRB- -LRB-) (NP (NP (NN fig) (NNS 2c)) (, ,) (NP (NNS 2d))) (-RRB- -RRB-))) (PP (IN until) (NP (DT the) (NN sensor)))))) (VP (VBZ touches) (NP (DT the) (NN coil))) (. .)))
Repeat moving coils and reading the magnetic field values (fig 2c, 2d) until the sensor touches the coil.
(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))))))) (. .)))