What is the relationship between the input voltage and output voltage in a transformer?

The relationship between the input voltage and the output voltage in a transformer is determined by the turns ratio, which is the ratio of the number of turns of wire in the primary winding to the number of turns in the secondary winding. This fundamental principle of transformer operation means that the output voltage can be either increased or decreased based on this turns ratio.

If the secondary winding has more turns than the primary winding, the transformer will step up the voltage, resulting in an output voltage that is higher than the input voltage. Conversely, if the secondary winding has fewer turns than the primary winding, the transformer will step down the voltage, producing an output voltage that is lower than the input voltage. The exact voltage is directly proportional to the number of turns in each winding, making the turns ratio a key factor in determining the relationship between the input and output voltages.

While it may seem intuitive that the output voltage must always be lower than or equal to the input voltage, that is not true when considering transformers designed for stepping up voltage. Additionally, the output voltage does not depend on the load connected to the transformer because it is primarily established by the turns ratio; however, the load can affect the output voltage under certain conditions, particularly in regards to efficiency and voltage drop.