Electrical engineeringLesson 1 of 5 in the course AC power

Alternating Current: Waveforms, Power Systems, and Signal Transmission

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Alternating current is a form of electric current that changes direction over time. It is the standard form of electricity delivered to homes and businesses, and it is also used to carry information.

Alternating current (AC) periodically reverses direction and continuously changes in magnitude. Direct current (DC) flows in only one direction. Batteries commonly supply DC, while wall outlets generally supply AC.

All flashcards

What is alternating current?
Electric current that periodically reverses direction and changes in magnitude over time.
What is direct current?
Electric current that flows in only one direction.
What does a waveform show?
How a quantity such as voltage or current varies over time.
What is a cycle?
One complete repetition of a waveform.
Name two uses of AC besides delivering power.
AC signals can carry information such as audio, radio, telephone, or video signals.

Quiz questions

  1. How does a transformer change AC voltage?Answer: Through electromagnetic induction between its windings.
  2. What is the protective purpose of bonding exposed metal parts of electrical equipment to earth?Answer: It provides a low-impedance fault path that helps overcurrent protection disconnect the circuit.
  3. Which description best characterizes a waveguide used for microwave signals?Answer: A hollow conductive tube that guides electromagnetic fields.
  4. For a sinusoidal voltage with no DC component, how is RMS voltage related to peak voltage?Answer: Vrms=Vpeak/2V_{\text{rms}}=V_{\text{peak}}/\sqrt{2}
  5. For a sinusoidal voltage, how does peak-to-peak voltage relate to peak voltage?Answer: It is twice the peak voltage.

Based on the Wikipedia article Alternating current, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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