What relation exists between the primary and secondary voltages and currents?

The relationship between primary and secondary voltages and currents in a transformer is described by the transformer equations. Specifically, the ratio of the primary voltage (V₁) to the secondary voltage (V₂) is equal to the ratio of the number of turns in the primary coil (N₁) to the number of turns in the secondary coil (N₂): V₁/V₂ = N₁/N₂. Similarly, the relationship between the primary current (I₁) and secondary current (I₂) is inversely proportional: I₁/I₂ = N₂/N₁. This means that if voltage is stepped up, current is stepped down, and vice versa, while the power remains approximately constant (ignoring losses).