How to Test an Ultrasonic Transducer: Impedance, Sensitivity, Ringing, and Pair Matching
An ultrasonic transducer cannot be accepted or rejected from its frequency label alone. “40 kHz” may describe a nominal operating region, while the measured resonance, impedance, bandwidth, sensitivity, and decay depend on construction, mounting, cable, temperature, acoustic load, and test method. A useful test plan begins with the decision it must support: incoming inspection, supplier comparison, circuit design, matched-pair selection, production screening, or failure analysis.