What is the result of a step-down transformer on voltage and current?

A step-down transformer is designed to reduce the voltage while increasing the current in an electrical circuit. The fundamental operation of a transformer relies on the principle of electromagnetic induction, where the voltage transformation is based on the ratio of the number of turns of wire in the primary coil (input side) to the number of turns in the secondary coil (output side).

In a step-down transformer, the secondary coil has fewer turns than the primary coil. This configuration causes the voltage in the secondary coil to be lower than the voltage in the primary coil. According to the transformer equation—voltage ratio equals the turns ratio—the voltage is decreased when there are fewer turns in the secondary than in the primary.

However, when the voltage decreases, the current in the secondary increases. This phenomenon is explained by the conservation of power in an ideal transformer, which states that the input power (voltage times current in the primary) equals the output power (voltage times current in the secondary). Mathematically, this can be expressed as:

[ V_1 \cdot I_1 = V_2 \cdot I_2 ]

Here, (V_1) and (I_1) represent the voltage and current in the primary