A transformer works on the principle of Faraday’s Law of Induction. Energy is transferred via a magnetic field, keeping the input and output circuits galvanically isolated.

The Core Formulas:

Ideal vs. Real: This calculator assumes 100% efficiency. In reality, transformers lose energy through Copper Loss (wire resistance) and Core Loss (eddy currents and hysteresis in the iron core).

Saturation: If you apply too much voltage to the primary, the magnetic core will “saturate,” causing the inductance to drop and the current to spike dangerously.

Frequency: Transformers designed for 60Hz (mains) are much larger than those designed for 100kHz (switching power supplies) because higher frequencies allow for smaller cores to transfer the same amount of power.