piezoelectric materials

Discussion in 'General Electronics Chat' started by bujak18, Dec 3, 2008.

  1. bujak18

    Thread Starter Active Member

    Nov 12, 2008
    Did you know that Quartz is not the only piezoelectric material?

    wheather or not you did or didn't know, what does this fact suggest to you?:rolleyes:
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    Piezo ceramics have been used for decades. The old ceramic phono cartridges were probably the best example. Quartz just has the highest Q, by far.

  3. bujak18

    Thread Starter Active Member

    Nov 12, 2008
    but what does Q mean or stand for
  4. leftyretro

    Active Member

    Nov 25, 2008
    It's a dimensionless number, that is a ratio.

    From Wikipeda:

    the Q factor is the ratio of the reactance to the resistance (or equivalently, the absolute value of the ratio of reactive power to real power)

    I might add that this Q factor is measured at the devices resonant frequency.

    PS: To give you a comparison of how good the Q factor of a quartz crystal can be, one might measure a good crystal and find it has a Q factor of 10,000 or more, where a given series L/C filter may only have a Q factor of 10. Quartz rystals have among the highest Q factor of any electronic components known and that is why they are used for oscillator and clock circuits when wanting the best frequency stablity possible.
    Last edited: Dec 4, 2008
  5. flat5

    Active Member

    Nov 13, 2008
    A crystal earphone (more properly called a piezoelectric earphone, pronounced pee-zo) is made of a material that changes its shape when connected to a source of electricity. Some crystals such as quartz, and Rochelle's Salt are piezoelectric. Some ceramics (such as those made with barium titanate) are also piezoelectric. Our piezoelectric earphone is made of a disk of brass that is coated with barium titanate ceramic. When electricity is connected to it, the ceramic bends the brass disk, and we can hear the vibrations this causes in the air.