Question

High-frequency noise in AC power can damage computers. Does the plug-in unit designed to prevent this damage use a large inductance or a large capacitance (in series with the computer) to filter out such high frequencies? Explain.

a) Large inductance to filter high frequencies.

b) Large capacitance to filter high frequencies.

c) Inductance and capacitance are both used.

d) Neither inductance nor capacitance is used.

Answer 1

To protect computers from high-frequency noise in AC power, a plug-in unit uses a large inductance in series with the device because inductors have higher reactance at higher frequencies, effectively filtering out the noise.

Step-by-step explanation:

To filter out high-frequency noise in AC power that can damage computers, a plug-in unit would typically use a large inductance in series with the computer. An inductor, when placed in series with a computer, impedes rapid changes in current due to its reactance, which is higher at larger frequencies. This characteristic allows the inductor to act as a filter for high-frequency signals, effectively reducing the high-frequency noise and protecting sensitive electronic equipment.

When an inductor is subject to high-frequency signals, it offers a larger reactance, which restricts the flow of these undesirable high frequencies but allows lower frequencies, such as the desired 50 Hz or 60 Hz AC power, to pass through with less impedance. Therefore, inductors are specifically chosen to protect against high-frequency interference because they are less effective at impeding low frequencies. The larger the inductance, the greater the reactance at a given high frequency, which translates into better filtering capabilities for the protection unit.