RLC Circuits

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The following animation illustrates the behavior of a series RLC circuit in an AC circuit. Impedance, phase shift, and resonance behavior are visualized in real time.

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Animation Description

The animation shows a series RLC circuit with four synchronized displays: circuit diagram, formulas, phasor diagram, and time-domain graph. The start button begins the animation. The phasors rotate and the sine waves move through the diagram.

The impedance of the circuit is calculated as:

\[ Z = \sqrt{R^2 + (X_L – X_C)^2} \]

With the reactances:

  • \( X_L = 2\pi f L \) – inductive reactance
  • \( X_C = \frac{1}{2\pi f C} \) – capacitive reactance

The phase shift φ between voltage and current is displayed as a double arrow in both the phasor diagram and the time-domain graph.

Interactive Controls

The following parameters can be adjusted using the sliders:

  • U (1–24 V): AC voltage amplitude
  • f (1–200 Hz): AC voltage frequency
  • R (1–1000 Ω): Resistance
  • C (1–100 µF): Capacitance
  • L (10–1000 mH): Inductance

The checkboxes L, C, and R allow individual components to be shown or hidden to examine different circuit configurations (e.g., pure RC or RL circuit).

Physical Background

In a series RLC circuit, three effects combine: R converts energy into heat, L stores it in a magnetic field, C in an electric field. The inductor and capacitor periodically exchange energy. The resistor dampens this oscillation.

At the resonant frequency \( f_0 = \frac{1}{2\pi\sqrt{LC}} \), the reactances cancel out (\( X_L = X_C \)), the impedance reaches its minimum and equals the resistance. The current reaches its maximum and is in phase with the voltage.

Practical Applications

  • Radio receivers: Tuned circuits select specific frequencies through resonance
  • Filters: High-pass, low-pass, and band-pass filters in audio engineering
  • Oscillators: LC oscillators for clock generation in digital circuits
  • Power factor correction: Capacitors compensate for inductive loads in power grids

Overview

TitleRLC Circuits
Target AudienceTeachers and Lecturers
FeaturesFull-screen mode
Lossless scaling
Large screens and projectors supported
LicenseMIT