What happens to the voltage in a step-down transformer?

In a step-down transformer, the primary function is to reduce the voltage from the primary coil to a lower voltage in the secondary coil. This occurs through the principles of electromagnetic induction and the turns ratio between the primary and secondary coils.

When the number of turns in the secondary coil is fewer than that in the primary coil, the transformer steps down the voltage. This reduction in voltage corresponds directly to the ratio of the number of turns in each coil, which is a fundamental design feature of step-down transformers. As a result, the voltage in the secondary coil is less than that in the primary coil.

Consequently, if the transformer is functioning correctly, the electrical energy is conserved, but the voltage decreases while the current increases, preserving the power output through the relationship defined by the formula: power in (primary) = power out (secondary). This principle is central to how step-down transformers are used in various applications, such as in power distribution systems, where high voltages need to be reduced for safe usage in homes and businesses.