“What’s the difference between a power spike and a power surge? How do I protect against them?”
Power Spike – A very short pulse of energy on a power line. Power spikes can contain very high voltages – up to and beyond 6000 volts – but usually last only a few milliseconds, as opposed to longer, but lower voltage power surge. Since they occur for such a short duration of time they don’t always cause equipment failure, but the potential is there for great damage to sensitive equipment and in many instances they can be catastrophic. Worse, while equipment may not fail right away when exposed to spikes, semiconductor devices can be “weakened” and may fail later. Modern power supply technology does a remarkably good job of filtering out moderate instances of these high frequency, high voltage components on the power line. Nevertheless they do almost always cause noticeable clicks and pops in audio and frequently will corrupt data in digital equipment. For very sensitive equipment and/or critical applications, additional power line filtering and voltage clamping can be deployed to further reduce the consequences of spikes.
Power Surge – A power surge is a temporary increase in voltage on a power line. Surges typically have less voltage than power spikes (usually 10% to 35% above the normal line voltage) but last much longer, from 15 milliseconds up to several minutes. Surges are common when power is supplied from lower quality generators. Sometimes surges are preceded or followed by spikes. Most modern power supplies can provide sufficient voltage regulation to protect equipment from everyday surges, but with very sensitive equipment and/or critical applications additional regulation is warranted. Voltage clamping devices such as spike protectors can help against some power surges, but this typically falls in the domain of something best handled by more of a voltage regulator.