What role does a transformer play in a power supply?

A transformer is an essential component in a power supply system primarily responsible for transforming voltage levels to desired values. Its fundamental operation is based on electromagnetic induction, which allows it to step up (increase) or step down (decrease) alternating current (AC) voltage levels as required for various applications.

Transformers consist of two or more coils of wire wrapped around a magnetic core. When AC voltage is applied to the primary winding, it creates a varying magnetic field, which induces a voltage in the secondary winding. The ratio of turns between the primary coil and the secondary coil determines the transformation ratio, effectively allowing the transformer to adjust voltage levels while maintaining the power (assuming ideal conditions with no losses).

This capability makes transformers critical in power transmission, where high voltages are used to minimize energy loss over long distances, and in power supplies for delivering the correct voltage needed by devices or circuits. Their fundamental purpose is to allow varied equipment to operate efficiently at their required voltage levels.