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ProblemsElectrical Power Basics
This section discusses very briefly the basics of electrical power. This is not a technically precise description, so I hope the electrical engineers will go easy on me. :^)
Electricity is, of course the flow of electrons through a wire. These electrons provide the energy that drives your computer and other devices. Electricity is described using four main characteristics: voltage, current, volt-amps and power.
The reason why volt-amps and power are of interest to the computer user is that the amount of power used by your computer equipment is typically expressed in watts, while the power supplied by uninterruptible power supplies, for example, is usually expressed in volt-amps. You must use a conversion factor to make sure you are not comparing apples and oranges.
The voltage on the line represents the force of the electricity, in terms of how much "push" it is making across the wire. If you compare the flow of electricity to the flow of water in a waterfall, the voltage represents how high the waterfall is; the higher, the stronger the flow of water. Voltage is measured in volts, abbreviated "V".
Current is a measure of how much electricity is in the line; how many electrons are moving through in a given unit of time. In the waterfall analogy, the current is how much water is going over the edge of the fall every second. Current is measured in amperes, or amps, abbreviated "A".
This is the product of voltage and current, and represents the total "raw" amount of power being supplied by the electrical source. It is measured (not surprisingly) in volt-amps ("VA").
Power is the amount of actual electrical work being performed over a period of time. It is measured in watts ("W"). If the load on the electrical line is a simple one (like a light bulb), power is equal to volt-amps, and the amount of power consumed is equal to the amount of power supplied. However, the PC power supply is a complex load, because of the way that it works to convert the power from the power line to the type used inside the PC. In this case, converting between volt-amps and wattage requires a conversion factor, which companies that make power equipment usually use as 1.4. Thus, volt-amps would be 1.4 times power in this case.
Next: External Power
Problems
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