( It ( ( consists ( of ( ( ( a ( thermionic tube ) ) ( with ( ( ( ( ( a cathode ) , ) ( an anode ) ) and ) ( a ( third electrode ) ) ) ) ) ( which ( is ( called ( the ( collector ( or ( counter electrode ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ consists) (PP (IN of) (NP (NP (DT a) (JJ thermionic) (NN tube)) (PP (IN with) (NP (NP (DT a) (NN cathode)) (, ,) (NP (DT an) (NN anode)) (CC and) (NP (DT a) (JJ third) (NN electrode)))) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBN called) (NP (DT the) (NN collector) (CC or) (NN counter) (NN electrode))))))))) (. .)))
It consists of a thermionic tube with a cathode, an anode and a third electrode which is called the collector or counter electrode.
(ROOT (S (NP (NP (DT The) (NN electrode)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (NN reduction)) (VP (VBZ occurs))))) (VP (VBZ is) (VP (VBN called) (NP (DT the) (NN cathode)))) (. .)))