( Voltage ( ( is ( ( the measure ) ( of ( ( ( how much ) energy ) ( ( ( ( ( each unit ) ( of ( electric charge ) ) ) has ) and ) ( current ( is ( ( the measure ) ( of ( ( how many ) ( ( units ( of ( electric charge ) ) ) ( are ( flowing ( each second ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Voltage)) (VP (VBZ is) (NP (NP (DT the) (NN measure)) (PP (IN of) (SBAR (WHNP (WHADJP (WRB how) (JJ much)) (NN energy)) (S (S (NP (NP (DT each) (NN unit)) (PP (IN of) (NP (JJ electric) (NN charge)))) (VP (VBZ has))) (CC and) (S (NP (JJ current)) (VP (VBZ is) (NP (NP (DT the) (NN measure)) (PP (IN of) (SBAR (WHADJP (WRB how) (JJ many)) (S (NP (NP (NNS units)) (PP (IN of) (NP (JJ electric) (NN charge)))) (VP (VBP are) (VP (VBG flowing) (NP (DT each) (NN second))))))))))))))) (. .)))
Voltage is the measure of how much energy each unit of electric charge has and current is the measure of how many units of electric charge are  flowing each second.
(ROOT (S (NP (NNP Voltage)) (VP (VP (VBZ is) (RB not) (NP (NP (DT the) (JJ same)) (PP (IN as) (NP (NN energy))))) (, ,) (CC but) (VP (VBZ means) (NP (NP (DT the) (NN energy)) (PP (IN per) (NP (NN unit) (NN charge)))))) (. .)))