A. Voltage
B. Current
C. Voltage & Current
D. Frequency
Answer: C. Voltage & Current
Explanation:
A Transformer changes the voltage level (or current level) on its input winding to another value on its output winding using a magnetic field.
A transformer transforms both current and voltage.
It is an electrical device that transfers electrical energy from one electric circuit to another, without changing the frequency.
A step-up transformer, step up the voltage and step-downs the current.
A step-down transformer, step-downs the voltage and step-ups the current.