( ( ( The power ) ( of ( a ( direct current ) ) ) ) ( ( is ( ( its voltage ) ( multiplied ( by ( ( it 's ) current ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN power)) (PP (IN of) (NP (DT a) (JJ direct) (NN current)))) (VP (VBZ is) (NP (NP (PRP$ its) (NN voltage)) (VP (VBN multiplied) (PP (IN by) (NP (NP (PRP it) (POS 's)) (NN current)))))) (. .)))
The power of a direct current is its voltage multiplied by it's current.
(ROOT (S (NP (NP (NNP Power)) (PP (IN in) (NP (NN electricity)))) (VP (VBZ is) (NP (NP (DT the) (NN voltage)) (VP (VBN multiplied) (PP (IN by) (NP (DT the) (JJ current)))))) (. .)))