Ultrasonic Transducer Technical Notes

http://www.olympus-ims.com/en/resources/white-papers/ultrasonic-transducer-technical-notes/

Knowledge Desk

https://www.meggittferroperm.com/resources/

Basics of Piezo Technology

https://www.ceramtec.com/competence/piezo-ceramics/

Fundamentals of Piezo Technology

https://www.piceramic.com/en/piezo-technology/fundamentals/#c13871

The Knowledge Center

https://www.americanpiezo.com/knowledge-center.html

Ultrasonics basics

https://piezotechnologies.com/ultrasonic-basics.php

Devision of Mide Technology

https://piezo.com/pages/piezo-education