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Question
Compare resistance and reactance.
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Solution
- Resistance:
- Resistance is opposition to the flow of charges (current) and appears in a DC circuit as well as in an AC circuit.
- In a purely resistive circuit, current and voltage are always in phase.
- Resistance does not depend on the frequency of AC.
- Resistance gives rise to the production of Joule heat in a component.
- Reactance:
- The term reactance appears only in an AC circuit. It occurs when an inductor and/or a capacitor are used.
- When reactance is not zero, there is nonzero phase difference between current and voltage.
- Reactance depends on the frequency of AC. In the case of an inductor, reactance increases linearly with frequency. In the case of a capacitor, reactance decreases as the frequency of AC increases; it is inversely proportional to frequency.
- In a circuit with pure reactance, there is no production of heat.
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