# Determining Total Power Consumption For A system

#### crazyengineer

Joined Dec 29, 2010
156
Lately I realized that I need to be able to understand the total power my projects would consume? Are there any techniques to find out how much power a system is consuming (e.g. power drawn by a 5V voltage regulator and power drawn from a DC motor system)?

#### wmodavis

Joined Oct 23, 2010
739
Measure the DC voltage applied to your project and the DC current flowing to your project and multiply those two values together.

P=V x I = total power consumed by your project.

Joined Dec 26, 2010
2,148
If the system has yet to be built, its power consumption can of course be estimated: how accurate an estimate you will get will depend on the quality of any assumptions it is based on, including things like component efficiencies which can vary between different types.

#### crutschow

Joined Mar 14, 2008
29,751
If you want the AC power the system uses, the easiest way is to buy a power meter such as the Kill A Watt. It measures voltage, frequency, power, VA , power factor, and total energy used over time.