Which formula calculates the efficiency of a transformer?

The formula that calculates the efficiency of a transformer is based on the ratio of output power to input power. Efficiency in a transformer is defined as the ratio of the power delivered at the secondary winding (output power) to the power supplied at the primary winding (input power). Therefore, the correct formula is the output power divided by the input power, often expressed as:

Eff = Psecondary / Pprimary.

This equation highlights how effectively the transformer converts input electrical energy into output electrical energy. A transformer operates by transferring electrical energy from the primary coil to the secondary coil with some losses due to heat and other factors, which is why the output power is always less than or equal to the input power. This formula provides a clear understanding of how much of the input power is converted into useful output power, reflecting the efficiency of the transformer in question.

Understanding transformer efficiency is crucial for engineers and technicians, as it indicates how well the device is performing and helps in assessing improvements or necessary adjustments for energy conservation.