( ( Resistors ( ( ( ( joined end ) ( to end ) ) , ) ( ( so ( ( that ( ( the current ) ( ( ( only ( has ( ( one path ) ( along ( which ( it ( may travel ) ) ) ) ) ) ) , ) ( are ( said ( to ( be ( connected ( in series ) ) ) ) ) ) ) ) ) . ) ) ( For ( ( the ( circuit segment ) ) ( shown ( below ( ( the ( potential difference ) ) ( between ( points ( ( A and ) B ) ) ) ) ) ) ) ) ) ) ) ( is V. ) )
(ROOT (SINV (S (NP (NNS Resistors)) (VP (VBD joined) (NP (NN end)) (PP (TO to) (NP (NN end))) (, ,) (UCP (SBAR (RB so) (IN that) (S (NP (DT the) (NN current)) (VP (VP (ADVP (RB only)) (VBZ has) (NP (NP (CD one) (NN path)) (PP (IN along) (SBAR (WHNP (WDT which)) (S (NP (PRP it)) (VP (MD may) (VP (VB travel)))))))) (, ,) (VP (VBP are) (VP (VBN said) (S (VP (TO to) (VP (VB be) (VP (VBN connected) (PP (IN in) (NP (NN series))))))))))) (. .)) (PP (IN For) (NP (NP (DT the) (NN circuit) (NN segment)) (VP (VBN shown) (PP (IN below) (NP (NP (DT the) (JJ potential) (NN difference)) (PP (IN between) (NP (NNS points) (NNP A) (CC and) (NNP B))))))))))) (VP (VBZ is)) (NP (NNP V.))))
Resistors joined end to end, so that the current only has one path along which it may travel, are said to be connected in series.  For the circuit segment shown below the potential difference between points A and B is V.
(ROOT (S (NP (NP (NNS Resistors)) (VP (VBN connected) (NP (NN end)) (S (VP (TO to) (VP (VB end)))))) (VP (VBP are) (VP (VBN said) (S (VP (TO to) (VP (VB be) (PP (IN in) (NP (NN series)))))))) (. .)))