Conceptual Questions
(a) Why does a capacitor act as a short circuit at high frequencies?
(b) Why does a capacitor act as an open circuit at low frequencies?

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Solution

(a) The capacitive reactance is proportional to the inverse of the frequency. At higher and higher frequencies, the capacitive reactance approaches zero, making a capacitor behave like a wire.
(b) As the frequency goes to zero, the capacitive reactance approaches infinity-the resistance of an open circuit.

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Conceptual Questions(a) Why does a capacitor act as a short circuit at high frequencies?(b) Why does a capacitor act as an open circuit at low frequencies?

Conceptual Questions
(a) Why does a capacitor act as a short circuit at high frequencies?
(b) Why does a capacitor act as an open circuit at low frequencies?