I'll leave this bit for the experts..
Tim, plug-in surge protectors shunt high voltage spikes to earth well enough - but the let-through voltage can still rise high enough to destroy sensitive electronics (like computers - especially newer computers).
The only real, practical, way to protect your computer against brownouts, surges and the like is to install a *quality* uninterruptible power supply (UPS). There are three types to choose from:
- "Off-line" - the cheapies you find in K-Mart, Dick Smith and Tandy. These units have little or no real surge protection (you blow up the UPS, not the computer it's attached to) and only switch to battery when the mains fails.
- "Line Interactive" - an off-line unit with a few more features. Some surge protection and switching to battery anytime the mains goes much above or below the correct output voltage.
- "On-line" - works off the battery all the time. The mains supply simply keeps the battery charged. These units are more expensive mainly because the batteries must be larger and be rated for constant use. Surge protection is guaranteed by the complete isolation of your computer from the incoming mains.
As with most things, you get what you pay for. To protect a PC, a line-interactive or true on-line UPS is the only way to go. The better brands include Powerware, MGE, APC.. Cheaper units like Sola have less surge protection and *will* need to be replaced after a decent surge.
In this country, everyone with an expensive computer setup should be connected to a UPS. You don't need a big one either - A$400 will get you a Powerware 5115 500VA one - more than enough for one PC.
Hope this helps, Cameron:-)