( It ( ( differs ( from ( ( ( a ( vacuum ( tube diode ) ) ) , ) ( which ( ( ( ( ( ( ( has ( only ( two electrodes ) ) ) , ) ( by ( having ( a ( third electrode ) ) ) ) ) , ) ( called ( ( the grid ) ( between ( the cathode ) ) ) ) ) and ) anode ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ differs) (PP (IN from) (NP (NP (DT a) (NN vacuum) (NN tube) (NN diode)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VP (VBZ has) (NP (RB only) (CD two) (NNS electrodes)) (, ,) (PP (IN by) (S (VP (VBG having) (NP (DT a) (JJ third) (NN electrode)))))) (, ,) (VP (VBD called) (NP (NP (DT the) (NN grid)) (PP (IN between) (NP (DT the) (NN cathode))))) (CC and) (VP (VBD anode)))))))) (. .)))
It differs from a vacuum tube diode, which has only two electrodes, by having a third electrode, called the grid between the cathode and anode.
(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)))) (. .)))