Measuring millivolts in dirty electricity

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populusnigra
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Measuring millivolts in dirty electricity

Post by populusnigra » Wed Jul 25, 2018 6:15 am

I wonder how this consultant is measuring dirty electricity in millivolts as showed in the photo below. He is using two probes, one measuring 120 V on Channel A (PicoConnect 442 supposing he is using a PicoScope 4444) and a second probe on Channel B but I wonder what type of probe he is using since the oscilloscope shows values in millivolts.

Image

I also include the video showing how he uses Picoscope for such a task:

https://www.youtube.com/watch?v=uBwLmQwvfeY

Thanks for your help.

Juan

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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Wed Jul 25, 2018 2:54 pm

If such a measurement is possible with the PicoScope 4444, I'm interested in knowing what type of probe should be used for measuring the millivolts present in the dirty electricity shown before. Thanks for your help!

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Re: Measuring millivolts in dirty electricity

Post by sbabic44 » Wed Jul 25, 2018 3:41 pm

Nobody knows what is he measuring... He's overdriving scope input ...
Also he is measuring "dirty electricity" .. That's snake oil...
If his electricity is dirty he should route it through dishwasher to wash it clean....
:roll:
He's a quack.. Ignore it.

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Re: Measuring millivolts in dirty electricity

Post by Gerry » Wed Jul 25, 2018 5:07 pm

Hi Juan,

To give you a more likely scenario to your question, it depends upon upon exactly where he's taking the measurement.

If he's measuring the live connection of a mains power supply (which would be the obvious choice) then he's probably using a suitably CAT rated Differential Probe to measure the 340V p-p (120V RMS) voltage. However, it's not necessarily a PicoConnect 422 as he is more likely to be using a PicoScope 2000 series, than a PicoScope 4444, because that's what he recommends on his website. So, it's more likely one of our active differential probes from here: https://www.picotech.com/accessories/ac ... ope-probes, and if the reason you asked the question is that you wanted to do this yourself, then I would strongly suggest that you find out how to choose an appropriate Active Differential Probe from our range, to make safe measurements, and start by reading our guide here: https://www.picotech.com/download/manua ... -probe.pdf (I'm not going to comment on the validity).

The red channel is more than likely not a Probe at all, but rather a Math Channel using a high pass filter to filter out the 60Hz period of the power supply waveform, leaving just the higher frequency noise and distortion induced onto the mains (which is easier to see on a smaller input range).

Regards,

Gerry
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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Tue Aug 21, 2018 3:20 pm

sbabic44 wrote:Nobody knows what is he measuring... He's overdriving scope input ...
Also he is measuring "dirty electricity" .. That's snake oil...
If his electricity is dirty he should route it through dishwasher to wash it clean....
:roll:
He's a quack.. Ignore it.
A quack? Really?. Eric Windheim is a certified Building Biology Ecology Consultant (BBEC) and Electromagnetic Radiation Specialist (EMRS) by the International Institute for Building Biology and Ecology.

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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Tue Aug 21, 2018 4:35 pm

Gerry wrote:Hi Juan,

To give you a more likely scenario to your question, it depends upon upon exactly where he's taking the measurement.

If he's measuring the live connection of a mains power supply (which would be the obvious choice) then he's probably using a suitably CAT rated Differential Probe to measure the 340V p-p (120V RMS) voltage. However, it's not necessarily a PicoConnect 422 as he is more likely to be using a PicoScope 2000 series, than a PicoScope 4444, because that's what he recommends on his website. So, it's more likely one of our active differential probes from here: https://www.picotech.com/accessories/ac ... ope-probes, and if the reason you asked the question is that you wanted to do this yourself, then I would strongly suggest that you find out how to choose an appropriate Active Differential Probe from our range, to make safe measurements, and start by reading our guide here: https://www.picotech.com/download/manua ... -probe.pdf (I'm not going to comment on the validity).

The red channel is more than likely not a Probe at all, but rather a Math Channel using a high pass filter to filter out the 60Hz period of the power supply waveform, leaving just the higher frequency noise and distortion induced onto the mains (which is easier to see on a smaller input range).

Regards,

Gerry
Hi Gerry,

Thanks for your reply. Sorry for not answering before but I had holidays in between. Yes, I think he is measuring right at the mains power supply which sounds the obvious choice in this case. The reason I mention the use of a Picoscope 4444 is because I already own a Picoscope 4444 and a PicoConnect 422. I will appreciate if you can confirm that using both the 4444 and 422 (plus the Math Channel you mentioned) is enough for measuring high frequency noise and distortion. For me is important to know if I still need an Active Differential probe for such a task.

Best regards,

Juan

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Re: Measuring millivolts in dirty electricity

Post by Gerry » Wed Aug 22, 2018 1:23 pm

Hi Juan,

The PicoConnect442 is a CAT III probe rated at ±1000V (which is DC + peak AC), so it is good for UK mains up to the wall socket, for instance, which is 230V RMS (and your voltage supply is not likely to more than 240V RMS which is also OK).

So No, you wouldn't need an Active Differential Probe.

Regards,

Gerry
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Re: Measuring millivolts in dirty electricity

Post by bennog » Wed Aug 22, 2018 2:18 pm

You can try the PicoConnect442 at the mains supply, and a 2nd channel at the output of a AC transformer.
Then make a math function to subtract both values.

then you get the HF part of the signal.

Benno

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Re: Measuring millivolts in dirty electricity

Post by Gerry » Fri Aug 24, 2018 11:46 am

Hi Benno,

I assume that you mean an Isolation transformer, as described here: https://www.allaboutcircuits.com/techni ... isolation/. This is not something that we suggest customers should use if they are not experienced in dealing with potentially hazardous voltages and currents, because it could allow a costly mistake, as explained in the paragraph below (from the link):
<<Sometimes the term “isolation transformer” is applied to transformers that isolate AC spikes, transients and noise, but maintain an earth ground connection. This type of transformer would not provide electrical isolation. You should verify the transformer you are using does provide electrically isolated outputs and doesn't supply an earth ground; check there is no continuity between the primary and secondary. If the transformer has a inter-winding screen, the screen should be connected to earth ground; also it's common practice to connect the transformer frame to earth ground as well.>>
Also, an isolation transformer would be extra cost, when a simple Math filter on the channel would achieve a similar result, see below.
Mains noise.psdata
(5.98 MiB) Downloaded 131 times
Regards,

Gerry
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Re: Measuring millivolts in dirty electricity

Post by bennog » Fri Aug 24, 2018 1:03 pm

Gerry,
No not the way you mentioned.
Use the PicoConnect442 to measure the mains voltage, use the 2nd channel to measure the output of a 6V AC transformer. (the AC transformer will filter out all higher frequencies)
Then subtract both values like in the attached sample.
Attachments
mains vs tranformer output.psdata
(281.42 KiB) Downloaded 98 times

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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Thu Oct 18, 2018 5:30 pm

Dear Gerry,
I'm returning to this post since I understand you could probably get the same results using a High pass filter, but if channel B is not a probe why it shows 200 mV AC voltage on the video. With the PicoConnect 442 you start from 2,5 V. I wonder what type of probe you need to use for getting 200 mV readings, any of the High voltage active differential probes you mentioned before?
Thanks a lot.

Gerry
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Re: Measuring millivolts in dirty electricity

Post by Gerry » Fri Oct 19, 2018 9:15 am

Hi Juan,

When using Math Channels you can over-ride the automatic scaling and provide your own scaling. So if you have performed a calculation and you expect the results to be up to 200 mV AC then you can specify that and the scale will be expanded to only show up to 200 mV of data.

Regards,

Gerry
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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Thu Nov 01, 2018 10:24 am

Hi Gerry,
I've already tried the Math filter you mentioned and works as expected. Thanks for recommending such a feature which is certainly worth exploring, I love it.
Best regards,
Juan

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Re: Measuring millivolts in dirty electricity

Post by Eric Windheim » Thu May 02, 2019 12:54 pm

I use the Picoscope 2204A, the Pico Active Differential Probe and a Stezter High Pass filter.

I use it to show clients what devices in their house create Dirty Electricity, DE, which causes neurological symptoms and biological damage. My goal is to reduce the DE by eliminating sources or filtering if necessary.[httpsyoutube]https://www.youtube.com/watch?v=eWYOHz__bc8&t=10s[/httpsyoutube]

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Re: Measuring millivolts in dirty electricity

Post by populusnigra » Fri May 03, 2019 7:50 pm

Dear Eric,
Thanks for your comments. Could you please explain how you use the Stezter High Pass filter in order to visualize and show dirty electricity to your clients?

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