Re: Ultrasonic

[Norman Lohstreter <petel@TENET.EDU>]

Hi David;

As I understand the operation, The metal disk is a support and one
electrical lead for a piezoelectric ceramic material.  When an
oscillatory potential is applied, the ceramic material distorts and
creates a longitudinal wave in the air.  The frequency is about 40 kHz,
therefore ultrasonic.  This frequency is pulsed at a rate that allows
the reflected wave to act on the ceramic in the reverse direction and
produce a potential between the two lead connected to the disk.  The
rest is electronics wave shaping and amplification.

David Abineri wrote:
> I had an occasion to repair a cbl ultrasonic motion detector recently.
> Looking at the sending (and receiving?) device, it looks like a pair of
> disks with two leads attached.  Does anyone happen to know the theory of
> operation of these devices? Just curious how something so apparently
> simple actually works.
>
> --
>         David Abineri     dabineri@choice.net

--
Pete Lohstreter                              "Reality is merely an
illusion,
The Hockaday School                           albeit a very persistent
one."
Dallas, TX 75229                                               A.
Einstein
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plohstreter@mail.hockaday.org
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