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Speaker 1: Welcome to brain Stuff from how Stuff works dot com

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Speaker 1: where smart Happens. Hi, I'm Marshall Brain For your computer,

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Speaker 1: electricity is essential, but it has to be the right

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Speaker 1: kind of electricity. What your computer expects to get from

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Speaker 1: the power grid in the United States anyway, is a

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Speaker 1: hundred and twenty volts AC power oscillating at sixty hurts.

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Speaker 1: A computer can tolerate slight differences, but a significant difference

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Speaker 1: will cause the computer's power supply to stop working or

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Speaker 1: to fail. A UPS or uninterruptable power supply protects a

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Speaker 1: computer against four different types of power problems. Voltage surges

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Speaker 1: and spikes. These are times when the voltage on the

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Speaker 1: line is greater than it should be. Voltage SAgs, times

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Speaker 1: when the voltage on the line is less than it

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Speaker 1: should be, a total power failure, times when the line

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Speaker 1: goes down or a fuse blows somewhere on the grid

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Speaker 1: or in the building and you have no power for

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Speaker 1: your computer. And frequency differences, times when the power is

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Speaker 1: oscillating is something other than sixty hurts. A standby UPS

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Speaker 1: runs the computer off the normal utility power until it

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Speaker 1: detects a problem. At that point, it very quickly in

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Speaker 1: five milliseconds or less, turns on a power inverter and

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Speaker 1: runs the computer off the ups IS battery. A power

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Speaker 1: inverter simply turns the d C power delivered by the

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Speaker 1: battery into clean volt sixty hurts a C power. Your

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Speaker 1: computer can usually run off a UPS for twenty minutes

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Speaker 1: or so. Do you have any ideas or suggestions for

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Speaker 1: this podcast? If so, please send me an email at

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Speaker 1: podcast at how stuff works dot com. For more on

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Speaker 1: this and thousands of other topics, go to how stuff

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Speaker 1: works dot com