Final answer:
A Surge Protector is an inexpensive device that can protect computers from AC power spikes by limiting excess voltage. It typically uses a large inductance to filter out high-frequency noise, providing both surge protection and noise filtration.
Step-by-step explanation:
To protect a computer against AC power spikes, one relatively inexpensive device that can be used is a Surge Protector. Surge protectors are designed to limit the voltage supplied to an electric device by blocking or shorting to ground any unwanted voltages above a safe threshold. This protection is vital because spikes can damage or degrade the sensitive components within computers and other electronic devices.
When dealing with high-frequency noise in AC power, a plug-in unit designed to mitigate this issue typically uses a large inductance or capacitance. Such a unit would use a large inductance in series with the computer to filter out high frequencies. Inductance depends on the frequency and the design of the inductor, while inductive reactance depends on both current and frequency. A surge protector often combines inductance with other components to provide comprehensive protection.