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314 views
07:24 Aug-04-2003
Akshay Singh
PZT film sensing

Hello:

I am using piezo films for sensing cracks in a substrate. I am having problems with dealing with the 60 Hz supply. It is appearing along with its harmonics in the entire frequency spectrum that I am looking at. I shielded the cables with Al foil, covered the film with Al foil but I am still picking up the 60 Hz. I would highly appreciate any suggestions. Regards.. Akshay


 
00:17 Aug-05-2003
Joerg Schulze-Clewing
Re: PZT film sensing Dear Akshay,

You'd have to provide some more info about your setup,
such as what frequency range you are using or maybe
which equipment.

Shielding doesn't have much effect at low frequencies
and it is usually better to use coupling transformers
that pass the desired frequency range and isolate
conductive paths. If harmonics are bothering you up
into the frequency range you are using then check for
noise "polluters" on the mains supply. I found one in
our lab yesterday and it was a plain old light dimmer
that had gone bad. It was showing up at several MHz
and after removing it that noise completely vanished.

All the best, Joerg.

----------- Start Original Message -----------
: Hello:
: I am using piezo films for sensing cracks in a substrate. I am having problems with dealing with the 60 Hz supply. It is appearing along with its harmonics in the entire frequency spectrum that I am looking at. I shielded the cables with Al foil, covered the film with Al foil but I am still picking up the 60 Hz. I would highly appreciate any suggestions. Regards.. Akshay
------------ End Original Message ------------





 
07:41 Aug-05-2003
Akshay Singh
Re: PZT film sensing Dear Joerg:

Thanks much for the response. You know what? It turned out the surge I was using had a problem with one of the outlet...:-). As soon as I plugged it in a different outlet...BAM...the 60 Hz died. As they say, more than often...the solutions are simple...Thanks again....Akshay

----------- Start Original Message -----------
: Dear Akshay,
: You'd have to provide some more info about your setup,
: such as what frequency range you are using or maybe
: which equipment.
: Shielding doesn't have much effect at low frequencies
: and it is usually better to use coupling transformers
: that pass the desired frequency range and isolate
: conductive paths. If harmonics are bothering you up
: into the frequency range you are using then check for
: noise "polluters" on the mains supply. I found one in
: our lab yesterday and it was a plain old light dimmer
: that had gone bad. It was showing up at several MHz
: and after removing it that noise completely vanished.
: All the best, Joerg.
: : Hello:
: : I am using piezo films for sensing cracks in a substrate. I am having problems with dealing with the 60 Hz supply. It is appearing along with its harmonics in the entire frequency spectrum that I am looking at. I shielded the cables with Al foil, covered the film with Al foil but I am still picking up the 60 Hz. I would highly appreciate any suggestions. Regards.. Akshay
------------ End Original Message ------------




 
01:22 Aug-06-2003
Joerg Schulze-Clewing
Re: PZT film sensing Dear Akshay,

Most surge strips contain metal oxyde varistors (MOV) which
are capping the spikes. When they do that they act like
a non-linear devices and create lots of harmonics. But
I'd like to add a word of caution:

If you try several suge strips from different manufacturers
and they all cause this problem that might indicate that
you have some equipment on the line that generates
spikes. Then it may be good to find out what equipment
that is because it can cause damage to lab instruments
that are connected to the line without a surge protector.

I mostly use a little AM radio to find out what causes
spikes or noise.

All the best, Joerg.

----------- Start Original Message -----------
: Dear Joerg:
: Thanks much for the response. You know what? It turned out the surge I was using had a problem with one of the outlet...:-). As soon as I plugged it in a different outlet...BAM...the 60 Hz died. As they say, more than often...the solutions are simple...Thanks again....Akshay
: : Dear Akshay,
: : You'd have to provide some more info about your setup,
: : such as what frequency range you are using or maybe
: : which equipment.
: : Shielding doesn't have much effect at low frequencies
: : and it is usually better to use coupling transformers
: : that pass the desired frequency range and isolate
: : conductive paths. If harmonics are bothering you up
: : into the frequency range you are using then check for
: : noise "polluters" on the mains supply. I found one in
: : our lab yesterday and it was a plain old light dimmer
: : that had gone bad. It was showing up at several MHz
: : and after removing it that noise completely vanished.
: : All the best, Joerg.
: : : Hello:
: : : I am using piezo films for sensing cracks in a substrate. I am having problems with dealing with the 60 Hz supply. It is appearing along with its harmonics in the entire frequency spectrum that I am looking at. I shielded the cables with Al foil, covered the film with Al foil but I am still picking up the 60 Hz. I would highly appreciate any suggestions. Regards.. Akshay
------------ End Original Message ------------




 
06:42 Sep-05-2003
Ryan Maladen
Re: PZT film sensing Dear Akshay/Joerg:
At IIT Delhi we are working on an PZT film sensor which is to be implanted to measure the intracranial pressure of an individual
The problem is we require to measure at a frequency of 1-10 Hz ....with PZT ceramics the same is not possible so cud u give me information regarding the usage of PZT film for my application
Thanks a ton
Looking forward to ur reply
----------- Start Original Message -----------
: Dear Joerg:
: Thanks much for the response. You know what? It turned out the surge I was using had a problem with one of the outlet...:-). As soon as I plugged it in a different outlet...BAM...the 60 Hz died. As they say, more than often...the solutions are simple...Thanks again....Akshay
: : Dear Akshay,
: : You'd have to provide some more info about your setup,
: : such as what frequency range you are using or maybe
: : which equipment.
: : Shielding doesn't have much effect at low frequencies
: : and it is usually better to use coupling transformers
: : that pass the desired frequency range and isolate
: : conductive paths. If harmonics are bothering you up
: : into the frequency range you are using then check for
: : noise "polluters" on the mains supply. I found one in
: : our lab yesterday and it was a plain old light dimmer
: : that had gone bad. It was showing up at several MHz
: : and after removing it that noise completely vanished.
: : All the best, Joerg.
: : : Hello:
: : : I am using piezo films for sensing cracks in a substrate. I am having problems with dealing with the 60 Hz supply. It is appearing along with its harmonics in the entire frequency spectrum that I am looking at. I shielded the cables with Al foil, covered the film with Al foil but I am still picking up the 60 Hz. I would highly appreciate any suggestions. Regards.. Akshay
------------ End Original Message ------------




 


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