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Re: Ultrasonic

Norman Lohstreter wrote:

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.

Pete, Since we can set the pulse rate (at least in the Pasco sonic ranger)
anywhere between 5 and 120 Hz, what is the pulse length? It's got to be
short enough to leave a suitable echo reception window even at the highest
pulse rate.

poj