How is electrical efficiency calculated in electrical systems?

Electrical efficiency is calculated by taking the output power of a system and dividing it by the input power. This ratio provides a measure of how effectively the electrical system converts input energy into useful output energy. The result is typically expressed as a percentage, which allows for easy comparison between different systems or technologies.

When determining electrical efficiency, it's important to note that the output power is the useful power delivered by the system, while the input power is the total power supplied to the system. A higher efficiency indicates that a larger portion of the input power is being effectively converted to output power, which is desirable in electrical systems as it implies lower energy losses, often attributed to resistive heating and other inefficiencies.

In contrast, other options such as the division of input power by output power would yield a value less than one, indicating inefficiency, while multiplying voltage and current provides power values but does not directly relate to the concept of efficiency.