Electrical Engineering 面试题与答案
问题 21. What is the significance of the power factor correction in electrical systems?
Power factor correction is employed to improve the power factor of a system, reducing reactive power and improving efficiency.
Example:
Capacitors are often used for power factor correction.
问题 22. Explain the concept of resonance in electrical circuits.
Resonance occurs when the natural frequency of a circuit matches the frequency of an applied alternating current, leading to maximum energy transfer.
Example:
Tuned circuits in radios use resonance for signal amplification.
问题 23. What is the purpose of a lightning arrester in power systems?
A lightning arrester protects electrical equipment from damage caused by lightning strikes by providing a low-resistance path for the surge current to the ground.
Example:
Commonly installed on power lines and substations.
问题 24. Define the term 'Joule heating' in electrical circuits.
Joule heating refers to the process where electrical energy is converted into heat in a conductor due to its resistance.
Example:
Incandescent light bulbs rely on Joule heating to produce light.
问题 25. What is a relay, and how is it used in electrical systems?
A relay is an electrically operated switch that uses an electromagnet to control the opening or closing of its contacts, allowing it to control high-power circuits with a low-power signal.
Example:
Used in control circuits, automation, and protection systems.
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