Electric Power
jimblom 
With Great Power...
Why do we care about power? Power is the measurement of energy transfer over time, and energy costs money. Batteries aren’t free, and neither is that stuff coming out of your electrical outlet. So, power measures how fast the pennies are draining out of your wallet!
Also, energy is...energy. It comes in many, potentially harmful, forms -- heat, radiation, sound, nuclear, etc. -- ,and more power means more energy. So, it’s important to have an idea of what kind of power you’re working with when playing with electronics. Fortunately, in playing with Arduinos, lighting up LEDs, and spinning small motors, losing track of how much power you're using only means smoking a resistor or melting an IC. Nevertheless, Uncle Ben’s advice doesn’t just apply to superheros.
Covered in this Tutorial
- The definition of power
- Examples of electric energy transfers
- Watts, the SI unit of power
- Calculating power using voltage, current, and resistance
- Maximum power ratings
Suggested Reading
Power is one of the more fundamental concepts in electronics. But before learning about power, there might be some other tutorials you should read first. If you're not familiar with some these topics, consider checking out those tutorials first:
- What is Electricity
- Voltage, Current, Resistance, and Ohm's Law
- What is a Circuit
- How to use a Multimeter