Thread: Piezo element?
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Old 12th Nov 2022, 2:37 pm   #3
Uncle Bulgaria
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Location: Cornwall, UK.
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Default Re: Piezo element?

Thank you Tony. I was struggling to find anything small enough! I have one of the circular ones at about 50mm in my parts box, and see eBay goes down to perhaps 15mm which is still too big. The original piece is rectangular, from what I can see beyond the corrosion, and they seem to be a rara avis.

Farnell does list one circular one, called a '9.5kHz sounder', in stock at 12mm diameter which may just fit. However, I'll need to bulk out the order a bit...

Some of the larger stand microphones used with a watch clipped between spring-loaded supports have a similar problem of no output, and corroded elements. However, with a bit more room in the body it's possible an available type of circular element will fit.

I'm surprised a single ECC83 is enough to amplify these signals. With the one microphone that seems to provide an output, I have to have the gain near full to distinguish the ticking on an earphone, and the drive doesn't seem to be enough to reliably fire the solenoid on the ticking.
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