>I'm still struggling to understand this subject of transducers, so let me
>ask what may be an extremely dumb question.  Digi-Key sells a 40 KHz
>ceramic transmitter for $9.20, and a 40 KHz ceramic receiver for $9.20.
>I would presume that means that the piezo-ceramic elements are resonant
>at that frequency.  If I pulse the transmitter with a 40 KHz square wave
>from a PIC, would it not transmit???  And if I hook an amplifier to the
>receiver, could I not receive that transmitted signal???

Yes it would. Only it would better if the 40kHz would not be exactly
40kHz, but slightly tuned to match the transmitter best. Driving 12V pk-pk
square wave into one of those will probably cover up to 20 meters of
distance under good conditions (or 3-4 meters when used as a sonar).

Peter

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