[SOLVED] UNI-T UT201 measuring DC current

[Darius051]

Hi to all. I have bought this clamp meter https://uni-trend.com/UT201.html# thinking that it would measure DC current but it does only AC. When I put the clamps around a DC source wire it however shows some results. I'm interested, are those readings accurate and is there a way to measure the DC current with this device after all?

Thanks :wink:

 

[FvM]

DC clamp meterss (using hall sensor) are available on the market. They can be intentified by a DC current line in the specification.

The present instrument doesn't have it and unfortunately can't be modified to support DC measurements.

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E.g. this one https://www.newark.com/tenma/72-7228/multimeter-digital-clamp-3-5-6/dp/01N4892

 

[Darius051]

Thank you FvM.
Just one question...what is my clamp meter measuring when I put it around a +DC source wire if it does not support DC measurements? I have some readings that are little bit oscillating 0,3A up and down. Hmm..:thinker:

 

[FvM]

You might see ripple current of an unfiltered DC source, or load generated ripple.

 

[Darius051]

Well, I connected a battery charger to the battery with another multimeter in series to measure the current on the + wire and then clamped the same wire with the UT201 and the measurements were almost exact. So if this clamp meter can measure this DC current like the other meter then I'm very satisfied. Or the device has some features that I'm not aware of...I'm a little bit confused. ;-)

 

[chuckey]

Battery chargers do not have any smoothing capacitors in them. So the waveform is a rectified sinewave that varies from zero to maximum current. The DC ammeter will indicate something between the average value and the RMS value of the peak current. Your clamp meter, because the change of DC current is linked via a transformer to the actual metering circuit, the metering circuit sees a highly distorted AC waveform which it then measures.
Frank

 

[Darius051]

Battery chargers do not have any smoothing capacitors in them. So the waveform is a rectified sinewave that varies from zero to maximum current. The DC ammeter will indicate something between the average value and the RMS value of the peak current. Your clamp meter, because the change of DC current is linked via a transformer to the actual metering circuit, the metering circuit sees a highly distorted AC waveform which it then measures.
Frank

Thnx, I have understood it now.:wink: