Lecture Notes: Phasor Diagram and Sound Wave Properties

Introduction to Phasor Diagrams

• Phasor Diagram:
  • Also known as a spinning wheel.
  • Represents frequency, amplitude, and phase of vibrations.
  • Useful for calculation and visualization of vibrations.

Components of a Phasor Diagram

• Phasor:
  • Rotates inside the spinning wheel.
  • Length corresponds to the radius of the wheel.
• Frequency:
  • Number of circular revolutions per second.
  • Represents the frequency of the sound wave.
• Amplitude:
  • Radius corresponds to amplitude of the sound wave.

Calculating Wavelength and Phase

• Wavelength (λ):

  • Calculated as the ratio of wave propagation rate (c) to frequency (f).

• Phase of a Wave:

  • Consider a red dot on the wave to describe its position or phase.
  • Distance (delta, δ) to the next zero crossing of the wave is crucial.
  • Phase Shift (φ):
    • Formula: φ = 2π * δ / λ
    • Describes the phase of the sound wave.*

Summary

• Phasor diagrams are essential tools for understanding and representing the properties of sound waves.
• They provide clear visualization and calculation methods for frequency, amplitude, and phase.
• Understanding the position and phase of a wave helps in precise characterization of vibrations.