Quartz crystal oscillator

  1. Quartz crystals are used in clocks to regulate time measurement.
    Does a quartz crystal convert heat energy to AC electrical energy?

    Duordi
     
  2. jcsd
  3. Bobbywhy

    Bobbywhy 1,908
    Gold Member

    Duordi, Welcome to Physics Forums!

    Quartz crystals do not convert heat energy to AC electrical energy. They are piezoelectric, which means they convert mechanical energy (say vibration) into electrical energy. Interestingly, they work in the reverse, also. When an electrical signal, say a voltage, is applied, the crystal deforms mechanically.

    You can learn all about them if you want to. May I suggest you begin with these two sites?
    http://www.electronics-tutorials.ws/oscillator/crystal.html
    http://en.wikipedia.org/wiki/Crystal_oscillator

    Cheers,
    Bobbywhy
     
  4. Re: so you agree

    So if a crystal was immersed in a gas which would strike the crystal every so often
    causing it to remain vibrating then the crystal would constantly provide an electric current.

    This may not be a useful condition because of its minute capacity but it would be a direct conversion of heat energy (motion of the gas molecules) to electrical energy.

    durodi
     
  5. Bobbywhy

    Bobbywhy 1,908
    Gold Member

    durodi, Interesting hypothesis, but I don’t think it works the way you propose. Did you visit the two sites I recommended? There the physical deformation of a crystal and the resultant charge generation is clearly described.

    A quartz (piezoelectric) crystal must be deformed along a particular axis in a well-defined direction in order to produce a voltage.

    A quartz crystal immersed in a hot gas will be bombarded by rapidly moving molecules. But they will impact on the crystal from all directions, and therefore exerting a force on the crystal in all directions. The result will not be any vibration, deformation, or voltage generated. So there would be no conversion of heat energy to electrical energy.

    Nice try, durodi. I encourage you to continue your searching. This is how new discoveries are made.

    Cheers,
    Bobbywhy
     
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