What is the basic construction of a transformer?

The basic construction of a transformer consists of two insulated coils wound around a common iron core. This design is fundamental because it allows electrical energy to be transferred between the two coils through electromagnetic induction. When alternating current flows through one coil (the primary coil), it creates a magnetic field that induces a voltage in the second coil (the secondary coil). The effectiveness of this energy transfer is enhanced by the presence of the iron core, which serves to concentrate and channel the magnetic field between the coils.

This construction is key to the operation of transformers, enabling them to either increase (step-up) or decrease (step-down) voltage levels in electrical systems, depending on the ratio of turns in the primary and secondary coils. The use of insulated coils ensures that the two circuits operate independently while still allowing for the inductive coupling required for the transformer to function.