Electrical engineeringLesson 1 of 3 in the course Reactive circuits

Capacitors: Construction, Circuit Behavior, and Practical Design

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

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Summary

This lesson introduces the capacitor as a component that stores electrical energy and traces the development of early capacitors. Understanding its construction and purpose provides a foundation for studying how capacitors behave in circuits.

A capacitor is a passive, two-terminal component designed to store electrical energy in an electric field. It has two conductors separated by an insulating region. The conductors are often metallic plates, foil, or thin films, while the insulating region is called the dielectric. A capacitor was historically called a condenser; the term survives in a few expressions, including condenser microphone. Informally, it may be called a cap.

All flashcards

What is a capacitor?
A passive two-terminal component that stores energy in the electric field between conductors.
What is the role of a dielectric in a capacitor?
It insulates the conductors and increases the charge stored for a given voltage.
What does the ideal capacitor current-voltage relationship describe?
Current is proportional to capacitance and the rate of change of voltage: i=C dv/dti=C\,\mathrm{d}v/\mathrm{d}t.
What is a Leyden jar?
An early capacitor in which a glass jar separated conducting regions.
What does equivalent series resistance (ESR) represent?
Resistive losses within a capacitor and its connections.

Quiz questions

  1. For an ideal capacitor with constant capacitance, which relationship connects charge magnitude QQ, voltage VV, and capacitance CC?Answer: C=Q/VC=Q/V
  2. In a series RC charging circuit, what does the time constant τ=RC\tau=RC indicate?Answer: The characteristic pace of the circuit's exponential voltage and current changes.
  3. For a sinusoidal voltage across an ideal capacitor, how does current phase relate to voltage phase?Answer: Current leads voltage by 90 degrees.
  4. How is the equivalent capacitance of capacitors connected in series calculated?Answer: Add the reciprocals of the individual capacitances, then take the reciprocal of the sum.
  5. What effect can a capacitor's ESR have when ripple current flows?Answer: It causes resistive losses that can produce heating.

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

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