How does a computers uninterruptible power supply UPS work?
What your computer expects to get from the power grid (in the United States) is 120-volt AC power oscillating at 60 Hertz (see How Power Distribution Grids Work for more information). A computer can tolerate slight differences from this specification, but a significant deviation will cause the computer’s power supply to fail. A UPS generally protects a computer against four different power problems: • Voltage surges and spikes – Times when the voltage on the line is greater than it should be • Voltage sags – Times when the voltage on the line is less than it should be • Total power failure – Times when a line goes down or a fuse blows somewhere on the grid or in the building • Frequency differences – Times when the power is oscillating at something other than 60 Hertz There are two common systems in use today: standby UPS and continuous UPS. A standby UPS runs the computer off of the normal utility power until
