Power problem can damage out electronic components in a matter of seconds. These power problems can be caused by an act of nature or human fault.
The following are power line problems and the damage caused to the computer by them:

Blackout: A blackout is a complete loss of electric power where voltage and current drop to almost zero. Blackouts are usually caused by physical interruption in the power line due to accidental damage by a person or act of nature. A loss of AC wills invariably shutdown the computer in a millisecond.

Loosing power may cause the loss of valuable data, reduction in productivity. In extremely rare cases, a sudden and complete power loss can corrupt file structure and damage files.

Brownout: The under voltage condition also called brownout or sag. The high load items like air conditioners, welding machine, motors etc… can draw to much current that the AC voltage level drops. When AC voltage falls outside of the tolerable range, the power supply will fall out of regulation, resulting in intermittent system operation.

Due to this system hang, random memory errors occur or file may be lost or corrupted on the hard drive.

Surge: These are small over voltage condition that takes place over relatively long periods. To regulate power to a desired level, excess energy must be switched in SMPS or dissipated away. In either case, excessive voltage creates overheating in the supply, and therefore damages the power supply.



Spikes: A spike is a large over voltage condition that occurs in the milliseconds. Lightning strikes and high energy switches can cause spikes on the AC line. Heavy equipment like drill machine, grinders, etc… can produce power spikes.

If the PC is on the same AC line as that heavy equipment, the spikes can damage the PC-SMPS.