Ace the 2025 Associate Certified Electronic Technician Exam – Spark Your Success!

The core of a transformer is typically made from iron, particularly silicon steel, because this material has excellent magnetic properties that enhance the efficiency of the transformer. Iron's ability to concentrate magnetic fields helps in the transfer of energy between the primary and secondary coils, significantly improving performance and reducing energy losses due to hysteresis and eddy currents.

Ferrite, which is a ceramic compound made from iron oxide mixed with other metals, is often used in high-frequency applications such as inductors and transformers for RF circuits due to its low losses at those frequencies. However, for standard transformers, particularly those operating at the electrical mains frequencies (50Hz or 60Hz), iron is preferred for the core material because of its superior magnetic characteristics compared to ferrite in those applications.

While copper and aluminum are commonly used for windings in transformers due to their excellent electrical conductivity, they do not serve as core materials. Their properties do not support the magnetic functionality required for transformer operation. Thus, when considering the optimal material for the core of a transformer, iron is the most suitable choice due to its ferromagnetic properties.