Final answer:
An isolation transformer consists of at least two coils: a primary and a secondary winding wrapped around a ferromagnetic core. These transformers provide electrical isolation while typically maintaining a 1:1 voltage ratio.
Step-by-step explanation:
An isolation transformer consists of a minimum of two coils (or windings). The construction of a typical isolation transformer involves a primary winding and a secondary winding, each with a number of turns wrapped around a laminated ferromagnetic core designed to minimize eddy currents. This configuration ensures that the magnetic field created by the primary coil is transmitted efficiently to the secondary coil, allowing for electrical isolation between the input and the output.
Isolation transformers are used where electrical separation is needed between the input and output, typically for safety reasons. For an isolation transformer, it's common to have the same number of turns on the primary and secondary windings, which provides a 1:1 voltage ratio, thus maintaining the same voltage level from input to output while still isolating the two circuits.