Electrical Craft Certification 4 Practice Test 2025 – All-in-One Guide to Master Your Certification!

A transformer functions primarily to change the voltage levels in an alternating current (AC) circuit. It operates on the principle of electromagnetic induction, where alternating current in the primary coil generates a magnetic field, which induces a voltage in the secondary coil. This allows for either an increase (step-up transformer) or decrease (step-down transformer) in voltage depending on the turns ratio of the coils.

The ability to change voltage levels is crucial in power distribution systems, as it enables electricity to be transmitted over long distances with minimal losses. Higher voltages result in lower currents for the same power transfer, hence reducing resistive losses in wires. This function is essential for efficient energy transmission and ensuring that electrical power can be delivered appropriately for residential, commercial, and industrial use.