When a transformer increases voltage, what effect does it have on the current?

When a transformer increases voltage, it operates under the principle of conservation of energy, which states that the power input must equal the power output (ignoring losses). The relationship between voltage and current in a transformer is inversely proportional, as described by the equation: Power (P) = Voltage (V) x Current (I).

When the voltage is stepped up (increased) by the transformer, the current must decrease to maintain the same power level. This means that for a higher output voltage, the output current must be lower to ensure that the power remains constant. Therefore, an increase in voltage leads to a corresponding decrease in current, which aligns with the answer indicating that the current decreases when the voltage is increased by the transformer.

This principle is crucial in understanding transformer functionality, where a step-up transformer, which raises voltage, will simultaneously lower the current on the secondary side.