Local photography, National rants, Zero navel-gazing allowed… Blogging from Hopkinsville, KY

Power Factor

Ha! Learning is fun. For Christmas, I received a P3 Kill-a-Watt. The device gives a reading on many statistics such as Volts, Amperes, Watts, Volt-Amperes, Hertz, Power factor, Kilowatt-hours, and total time connected. After using it for a short while, I wasn’t familiar with the terms volt-amperes and power factor. The Wikipedia article on power factor explained it best.

The significance of power factor lies in the fact that utility companies supply customers with volt-amperes, but bill them for watts. Power factors below 1.0 require a utility to generate more than the minimum volt-amperes necessary to supply the real power (watts).

Example: While I write this blog entry, my laptop draws from the wall 40 volt-amperes but only uses 19 Watts. The laptop has power factor of 50% because half of the current is returned back to the power plant without being used