Protecting computer systems against power transients

The sources of electrical transients, broadly interpreted as occurrences of any disturbance, either on the power line or the computer system´s data line, are reviewed. Common transients are overvoltages due to lightning strikes, transients caused by switching sequences in the power system, and undervoltages which could be caused by a nearby start-up of heavy loads or by distant faults. The impact of transients on small stand-alone and on distributed computer systems is examined. Growing concern among computer users that power-line surges, in particular, may damage equipment or cause loss of data has created a market for surge suppressors. Some guidelines are provided for choosing a protective device for both types of systems mentioned above. Potential negative side effects are indicated.<>