Circuitry consisting of MOVs, capacitors, rod-core inductors etc. for suppressing surges and spikes usually embedded in a power strip.
Surge
An substantial increase in voltage lasting a small fraction of a second, often caused when high powered appliances such as air conditioners are switched off.
Standby UPS
A type of uninterruptible power supply that remains in standby mode offering little or no power conditioning unless the voltage exceeds a set limit. If the voltage limit is exceeded, the UPS can support the load until the voltage returns to within the limits or the battery is drained.
Spike
An tremendous increase in voltage over a very short period of time often caused by a direct lightning strike on a power line or when power returns after a blackout.
Serial Port
A special cable plugs into the UPS and the computer's serial (RS232) port.
Sag or Brownout
Decrease in voltage levels which can last for periods ranging from fractions of a second to hours. Can be caused by heavy equipment coming on line such as shop tools, elevators, compressors etc. Also occurs when utility companies deliberately do this to cope with peak load times.
