Piezo buzzer testing for defects using electrical parameters

Question

I am looking for methods to verify whether a Piezo is damaged/defective or good. Are there ways to verify that using just electrical parameters like resistance, capacitance etc.

My issue is that it's not feasible to test dB levels using a handheld meter at the assembly line, so I was wondering if there are electrical parameters which we can test for other than sound level or current consumption (that actually need to turn on the device, specially the piezo unit).

Right now, the Piezo that I am using has a Vpp of 30 V and capacitance of 150 nF and being driven by an H-bridge.

• A Good Piezo: Sound is sharp and unbroken
• A Bad Piezo: Sound is distorted/broken (generally lower dB level than Good Piezo), sort of double sound, always an effect of damaged piezo while assembly
• Damaged Piezo: No sound at all

I am more interested in differentiating Good vs Bad Piezo:

• So, if I can measure some electrical parameters and define a ballpark for Good piezo
• If measured values are out of that range, it is not good and can be discarded

Here is link to the product: AB4113B

Acceptable methods of testing:

• Using Multimter/LCR
• Oscilloscope/Function Generator
• Any other parameter testing method that can be integrated in a test jig for production testing

Answer 1

I would suggest measuring the 'Q' and resonant frequency of the transducer, along with capacitance (should be within an acceptable range) and resistance (should be really high).

That should detect bonding and mounting issues as well as outright failure of the connections and that sort of thing.

I would also test 100% for SPL for a while initially and spot and lot checks later, even if it costs a bit more to move them to a place where they don't deafen the workers or supply PPE. It's very expensive to repair a reputation and it's possible some defects only show up at high SPLs.