What is Apparent Power?
Apparent power is the combined power value that is obtained by allowing for the different values of current and voltage. Essentially, the measure of apparent power is achieved by multiplying the applied voltage to the current generated. Most electrical systems operate by the use of apparent power. There are a few basic understandings about the nature of apparent power that help to define the nature of the power. Components of both reactive and real power must be present in order for apparent power to exist. That is, the load must be both reactive and resistant in order for the flow of apparent power to take place, and thus create a means for measuring the nature of the generated power. In addition to the presence of resistant and reactive loads, it is also important to determine the watts involved in the current as well. Just as in determining the rate of any complex power, knowing the watt value is key to understanding the nature of apparent power. In the actual calculation of apparen
Apparent Power is derived from multiplying Voltage by Ampere’s, which equals Volt-Amp’s. So for example if a 19″ Samsung SyncMaster 900IFT monitor draws 120V, 1.2A, the apparent power load is 120 (x) 1.2 = 144VA. While a good rule of thumb for monitors, calculating apparent power by looking at the specs on the side of the PCs power supply isn’t very helpful for a whole bunch of reasons which are beyond the scope of this review. A 500W Vantec Ion power supply may be rated for a maximum load of 10A at 120V, but in real life it probably won’t come anywhere near that 1200VA requirement. To accurately determine apparent power, P3 International sell a handy meter called the Kill-A-Watt which you can plug into the wall, and measure loads of up to 1875VA. If this all seems a little confusing, don’t fret. As an example, in this review we test the Powerware 5125 UPS with a 19″ CRT monitor and pretty standard 2.0GHz Pentium4 computer whose combined power draw is about 300VA. In other words, the 1
