Section 3 Waves


Oscilloscope wave traces

  • If a microphone is connected to an oscilloscope, the sound received by the microphone is transferred electrically and the oscilloscope trace can be used to compare frequency (pitch) and amplitude (loudness).
  • The diagrams show graphical representations of sound waves as seen on an oscilloscope screen.
    large amplitude  small amplitude
  • Notice that the frequencies of the loud sound and the quiet sound are the same in the traces above. Only the amplitude is different.
    high pitch  low pitch
  • Notice that the amplitudes are the same for the high- and low-pitch sounds in the lower two diagrams. Only the frequency differs.
  • Remember: Sound waves are longitudinal waves and not transverse waves. The diagrams above are graphical representations of the pressure variations.
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