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Products => Test Equipment => Topic started by: William_K on December 31, 2023, 11:51:46 pm

Title: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: William_K on December 31, 2023, 11:51:46 pm
Hello guys

Will start dealing with little thicker and beefier piezos soon and a SA will be invoved in that.

It's a very known fact that if you mechanically move a piezo it generate a voltage and if fast and hard enough that could be very high, it feels very much that this is something that had to be though about when testing this, or? The same with a waveform generator, any risk involved at all?

The SA cost 2k+ so I want to be dam sure about this and thus I ask before I test.

Regards William
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: tautech on January 01, 2024, 12:52:30 am
Why a SA and not a DSO ?  :-//
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: xrunner on January 01, 2024, 01:04:55 am
Quote from: tautech on January 01, 2024, 12:52:30 am
Why a SA and not a DSO ?  :-//

Yea really. Or -

Let me ask this. What are you trying to observe William_K? The wideband frequency spectrum of a piezo? Just attach a BNC cable to the input of your spectrum analyzer and at the other end a small coil of wire to the center conductor. Do not attach this to the piezo! Simply move it near enough to observe the spectrum.
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: William_K on January 02, 2024, 04:03:40 pm
Sure a DSO could work as well I guess, but there is a TG on the SA so I though using that somehow for it all? There might be more than one resonance in it due to reasons I cant go it to and thus I would like to see a little bit over and under its resonance frequency what is happening there.
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: AVGresponding on January 02, 2024, 04:45:29 pm
Inverse parallel diodes across the input?
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: William_K on January 03, 2024, 12:13:42 am
That could be a choice I think, thanks. I would prefer so it could free running to what ever voltage it would, but that could be clamped with diods or even a zener I guess then.
Title: Re: Little bigger piezo + Spectrum Analyser = destroyed input?
Post by: AVGresponding on January 03, 2024, 11:24:40 am
It'll clip, yes, but then you have a chance to reduce the input amplitude until it doesn't.