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Project Notes

#596 OpAmp Piezo Driver

Testing a circuit for driving a piezoelectric transducer for sound output with a TL072 opamp oscillator.

Build

Notes

As discussed in LEAP#455 Piezo Transducers and Buzzers, piezoelectric transducer require an external oscillator to produce sound.

This is an example of an OpAmp driver:

  • comparator-based relaxation oscillator implemented with one OpAmp from a TL072
  • 2N7000 switch to enable the oscillator
  • driving a passive buzzer element

NB: I have seen silimar circuits with an NPN BJT switch but some of these don’t seem to turn the oscillator hard enough off.

Construction

Breadboard

Schematic

Build

Results

Works fine - emits a constant tone when the button is pressed.

A crude estimate just considering the 20kΩ and 10nF RC path suggest a frequncy ~796 Hz. Actually 844Hz acording to the scope..

output

Credits and References

About LEAP#596 OscillatorsCrystalAudio
Project Source on GitHub Return to the LEAP Catalog

LEAP is just my personal collection of electronics projects - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting.

Projects are often inspired by things found wild on the net, or ideas from the many great electronics podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.

For a while I have also included various scale modelling projects here too, but I've now split those off into a new repository. Check out LittleModelArt if you are looking for the modelling projects!

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