Watt
The SI unit of power — 1 joule per second.
Definition
The watt (W) is the SI unit of power, defined as one joule per second. It measures the rate of energy transfer or conversion. Named after James Watt, the Scottish inventor who improved the steam engine. One horsepower equals approximately 745.7 watts.
Formula
1 W = 1 J/s = 1 kg·m²/s³
Examples
- A typical LED light bulb uses 8–12 watts.
- The human brain consumes about 20 watts.
- 1 horsepower = 745.7 W.