Author Topic: Choosing bandwidth on an oscilloscope current probe  (Read 1170 times)

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Offline 6SN7WGTBTopic starter

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Choosing bandwidth on an oscilloscope current probe
« on: December 12, 2022, 06:57:38 pm »
I am about to purchase a Micsig 2100A or B.

I already have a Rigol MSO5000 series 'scope and the rather good Micsig DP-750 diff probe.

My intended purpose is primarily power quality analysis - AC 50Hz driven SMPS and other PSUs, with secondary analysis of valve amplifier and test equipment.

What I'm not sure enough about is what bandwidth I actually need i.e. the A or B version, and would appreciate some sage advice. To some extent the seeming over-performance of the A has thrown a spanner into the works.

I CAN run to the B version so if it ends up as A OK but B more desirable then I'm OK with that.

Thank you.
 

Offline 6SN7WGTBTopic starter

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #1 on: December 13, 2022, 04:37:40 pm »
No-one, really?
 

Online Martin72

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #2 on: December 13, 2022, 09:12:52 pm »
Hi,

You know "my" thread about the micsig currentprobe ?

https://www.eevblog.com/forum/testgear/micsig-current-probe-cp2100b-tests-and-comparing/msg3072460/#msg3072460

The 800khz version could be enough for your purposes but be aware that the clamp is not the smallest on the market.
When using power analyzis on the rigol, don´t forget the channel deskew between voltage and current probe.

Offline Fungus

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #3 on: December 13, 2022, 09:14:53 pm »
A is OK and will do what you want but B is obviously more desirable.

 

Online Hydron

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #4 on: December 14, 2022, 04:37:47 am »
The "800kHz" one I got for work seemed to have a -3dB point of >2.5MHz, so not really sure how they decide what differentiates the A and B versions. Maybe I just got lucky? Or maybe there is something more subtle they use to pick the best ones to sell as the higher BW model?
 

Offline 6SN7WGTBTopic starter

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #5 on: December 14, 2022, 07:32:44 am »
Hi,

You know "my" thread about the micsig currentprobe ?

https://www.eevblog.com/forum/testgear/micsig-current-probe-cp2100b-tests-and-comparing/msg3072460/#msg3072460

The 800khz version could be enough for your purposes but be aware that the clamp is not the smallest on the market.
When using power analyzis on the rigol, don´t forget the channel deskew between voltage and current probe.

Yes Martin, a really good thread and without it I probably would not have spotted the need to deskew.

It did seem the B may just be a 'selected' version although thought I saw that it has one additional component on the main PCB.

Putting the question a different way, what sort of tasks would I  NOT be able to do with a B vs. an A?
 

Online Martin72

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Re: Choosing bandwidth on an oscilloscope current probe
« Reply #6 on: December 14, 2022, 10:40:29 pm »
Hi,

Good question.. ;)

For correct amplitude measure the signal´s frequency should be under the bandwith of the clamp.
For correct displaying the waveform (square) you got more "reserves", otherwise the signal looks like the pic below.
(measured with a clamp which bandwith is 120khz).
What else....Actually I don´t know, maybe other do.



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