Definition : Electric devices that consist of two or more coils usually wound around a magnetic core and that are coupled by mutual induction. Most transformers are used to change the voltage of an alternating current (e.g., step-up and step-down transformers). The ratio of the voltage on each coil is proportional to the number of turns, while the ratio of the currents is inverse to the number of turns. Some transformers are used for other purposes, such as isolation between the coils (e.g., primary and secondary windings) or for impedance transform.
UMDC code : 18562