Before we can discuss power conditioning, we must first explain what electrical noise can be, and how it can affect all your computer equipment.
A good analogy to use to explain electrical noise is to remind you of what you may see on your television when you turn on a power drill. The “snow” or static on your television screen is electrical noise affecting your antenna’s reception of the broadcast signal. This same “noise” is also present in the electrical power outlet. Today’s computers, terminals, printers, and other sensitive electronics use transistorized, internal power supplies. These power supplies do not have isolation transformers in them, so this same “noise” bouncing around your electrical outlets is allowed to sneak into your computer equipment. A “noise” spike as small as .5 volts peak-to-peak can “float” around on your circuit boards, and into the computer’s logic circuits, and confuse your computer into thinking a real voltage is present.
These “noises” that infiltrate your computer circuitry can cause things as simple as a “lock up” or a printer to stop printing, all the way to freezing the entire system, corrupting data on the disk, or burning out components. In most cases (except component failure) resetting or re-booting your computer fixes things, and “magically” everything is okay again, until the next time.
Common Mode noise and Normal Mode noise can be measured with power testing equipment and viewed on an oscilloscope. The brands that have been tested and recommended by Visum® for power conditioning are PowerVAR and ONEAC. These units provide isolated grounds (thereby eliminating potential “ground loops”), lightning protection, and common and normal mode noise rejection. These are low-output impedance devices that will not current-starve your computer equipment. High-output impedance conditioners will reject noises, but will over-work your equipment’s power supply and cause premature burnout.
