Contents
Key Stage 4
Meaning
Power efficiency is a ratio of useful power transferred to total power put into a system.
About Efficiency
- Power efficiency is a measure of how effectively energy is transferred from one energy store into an intended energy store.
- Efficiency may be written as a percentage or as a decimal.
- Efficiency as a percentage can never be greater than 100% and as a decimal can never be greater than 1 because you can never get more energy out than you put in due to Conservation of Energy.
Equation
Efficiency = (Useful Power Out)/(Total Power In)
\(Efficiency = \frac{P_{Useful}}{P_{Total}}\)
Where:
EUseful = The Useful Energy transferred to a device's intended purpose.
ETotal = The Total Energy transferred to a system.