Transformer :  (noun)

1: an electrical device by which alternating current of one voltage is changed to another voltage

agent, alembic, alterant, alterative, alterer, anvil, caldron, catalyst, catalytic agent, crucible, engine, ferment, innovationist, innovator, introducer, lathe, leaven, machine, melting pot, modificator, modifier, mortar, motor, precursor, retort, test tube, transducer, transmogrifier, yeast,