Efficiency Calculator
Calculate efficiency (e.g., mechanical, electrical) from input and output values.
Efficiency Calculation
Understanding Efficiency
Efficiency is a measure of how effectively energy or power is converted from input to useful output. It is typically expressed as a percentage, where 100% efficiency means all input is converted to useful output with no losses.
Efficiency Formula
Efficiency (%) = (Useful Output / Total Input) × 100%
Types of Efficiency
- Mechanical Efficiency: Ratio of mechanical power output to mechanical power input.
- Electrical Efficiency: Ratio of electrical power output to electrical power input.
- Thermal Efficiency: Ratio of useful heat output to total heat input.
- Overall Efficiency: Combines multiple stages of energy conversion.
Typical Efficiencies of Devices
| Device | Approximate Efficiency (%) |
|---|---|
| Incandescent Light Bulb | 5-10 |
| LED Light Bulb | 50-90 |
| Electric Motor | 70-95 |
| Gasoline Engine | 20-35 |
| Power Supply (AC-DC) | 75-95 |
Frequently Asked Questions
Why is no system 100% efficient?
According to the laws of thermodynamics, some energy is always lost during conversion, typically as heat, due to friction, resistance, or other dissipative processes. This means no real-world system can achieve 100% efficiency.
What is the difference between power and energy efficiency?
Power efficiency refers to the ratio of output power to input power at a given moment. Energy efficiency refers to the ratio of useful output energy to total input energy over a period of time.