is: a device that can change (transform) an a.c. voltage, from one value to another, with high power transfer efficiency. [P4.4]
consists: of two coils wound on a common core, with the primary coil connected to an a.c. input. [P4.4]
works: because mutual induction produces an induced voltage in the secondary coil. Depending on the transformer turns ratio, the induced voltage on the secondary coil may be stepped up or down compared with the voltage on the primary coil. [P4.4]
Copyright 1997, The Open University