Good clamp meter for low DC currents

[ElectricPower]

Just wonder witch clamp meter i should buy if my main usage was to measure low DC currents in mA and uA with highest possible accuracy?

Is the EEVblog BM036 a good coice? Or can i buy something cheaper?

[wasedadoc]

Measuring such low dc currents with a clamp meter is prone to large errors.  The device is essentially measuring measurement magnetic field.  The wanted component is produced by the current you are trying to measure.  But other unwanted components come from the earth's magnetic field and other objects such as your screwdrivers, metal toolchest, vehicle engine and bodywork etc.  When set to measure dc current, clamp meters have a 'zero' button to null those out but the slightest movement of the meter changes those unwanted components and gives an error in your reading.

You can make the wanted field stronger if it is possible to have multiple turns of the wire passing through the clamp.  You then need to scale down the reading it gives you.

[DaneLaw]

What's your budget as it gets expensive fast if you want uA-clamp measurement ability?
uA in DC clamp regi?  gonna be a challenge to clean out for your "highest possible accuracy" and not drift.

I recall the UnitT 211B and the corresponding mocked-up Extech M63 can do uA on the clamp, but usually only in AC where they can muster 0.1mA resolution
An overall decent cheap AC&DC clamp meter for milliamp is the old UT210E, though not sure what they are going for here in late 2023 or if there are better alternatives for the price, as the UT210E got quite a few years/decade under its belly.. - many alternative models will nowadays do DC 1mA clamp measurement and quite a bit cheaper with dual display (freq) and higher native display count.

Previously the UT210E was around 30 to 35US delivered.. - for that price it's a decent low current (1mA res) DC clamp meter, but you will cycle that zero-button to the cows come home when pursuing DC readings down to the last mA to keep these hall sensors in check.

[Martin72]

Hi,

Is the EEVblog BM036 a good coice?

Lowest range is 60A....

A current clamp meter that can measure mA accourate is not cheap and cannot be cheap.
We (work) bought one from Benning to be able to measure standby currents.
We have it calibrated regularly and the accuracy is good.
But it is very sensitive, the maximum currents must not be exceeded, it can only measure up to 10A.
But it can also measure mA.

Benning CM11

[J-R]

Many clamp meters can measure uA through the test leads albeit with a pretty hefty voltage drop.  The BM036 does not have this uA feature, but the BM037 does.  However, the clamp is not going to give you any usable mA capabilities.

When I was searching for a DC mA clamp back in the day I settled on the Fluke 771.  It has 0.01mA resolution at the lowest range and can measure up to 110mA.  They are readily available on the second hand market.  0.01mA accuracy is possible with some care, 0.1mA is pretty easy and 1mA is basically guaranteed no matter the conditions.  However, it's very limited otherwise.  It's really made for a specific purpose (4-20mA loop signals).

Instead, could you make some kind of resistor shunt test fixture that could be easily inserted into your circuit?

[BILLPOD]

Check out the Owon CM2100 and the CM2100B, (which has Bluetooth capability).   I just got one in the mail, but haven't had a chance to test it out.    Several reviews on the interweb, (Tony Albus' is the best).

[HKJ]

With AC you can find clamp meters designed for earth leakage that can measure low current, for DC it is much harder due to the earth magnetic field. The best DC clamps I have seen can measure within a few mA (When used with care).
My preferred clamp meter for low current DC measurement  is the Benning CM11 (It can also do AC), it has 0.1mA resolution on both DC and AC.

[Pfriemler]

Got me a cheap Voltcraft with a 4A range. If you clamp the meter around the wire with no current, activate the REL function and then switch on the current, you may get a reading in mA range. But once you exceed the 4A only, you will get useless random readings. Hoped to get an mA clamp, but it´s almost crap.

[Kean]

Another vote here for the Fluke 771... if you must use a current clamp.  As mentioned it has a 0.01mA resolution, but realistically it can struggle with that and would require re-zeroing under any change in position or conditions.  Mind you, I just checked mine against a reference current source and it was pretty well spot on for several 1mA or 0.1mA steps, including up to the max 110mA.

I did use my Fluke 771 for low current measurements many years ago when I first got it, but I quickly realised it was much easier to just break the loop an insert a current meter.  Then even nano or pico amp measurements become (somewhat) easy.  And there are many designs published to assist with low burden current measurement.

Now my Fluke 771 is just something I would use for checking the occasional 4-20mA current loop as it was intended.

I have no idea how well the suggested Benning or Owon clamp meters would compare in real life, but the Fluke does way better than any of my UT210Es at low currents.

[Martin72]

I have no idea how well the suggested Benning or Owon clamp meters would compare in real life

"Next year" I can have a look at the calibration report of the Benning.
It is about ten times as expensive as the Owon and explicitly designed for low currents, so it will probably be good for something.
The Owon sounded so interesting to me that I ordered it and it should arrive tomorrow.
Then I can compare it with the current range of my 6.5 digit meter.

[linux-works]

and if you want linux remote control of that owon clamp, go to my github and enjoy.

https://github.com/sercona/Owon-Multimeters

[Martin72]

I recently found a current clamp meter that has a dedicated mA range and is still cheap (under 100):

[csuhi17]

The peaktech has a resolution of 1 mA and its accuracy is +/- 2.5 % + 30 dgt.
with a measuring range of 5000mA.
The Owon has a measurement limit of 2,000A, also on a 1mA scale. accuracy ±(2%+8dig)...

[Brumby]

As a cheapskate with not very demanding requirements, I can attest to the usefulness of the UT210E.

You really do have to consider ALL external sources of magnetic fields, but developing a technique and using the "zero" button has proven to give reasonably repeatable measurements. Measuring in the hundreds of uA isn't where it will shine, but - with a well practised technique - you might get some indicative measurements.

[Martin72]

The peaktech has a resolution of 1 mA and its accuracy is +/- 2.5 % + 30 dgt.
with a measuring range of 5000mA.
The Owon has a measurement limit of 2,000A, also on a 1mA scale. accuracy ±(2%+8dig)...

Oh, that makes it much more accurate, doesn't it?

@Brumby:
I also have a Uni-T UT210e here, so I can compare it.

[Someone]

As a cheapskate with not very demanding requirements, I can attest to the usefulness of the UT210E.

You really do have to consider ALL external sources of magnetic fields, but developing a technique and using the "zero" button has proven to give reasonably repeatable measurements. Measuring in the hundreds of uA isn't where it will shine, but - with a well practised technique - you might get some indicative measurements.

Wrap the/a wire n times around the clamp jaw, n times the sensitivity.

[Brumby]

[Wrap the/a wire n times around the clamp jaw, n times the sensitivity.

That applies to any clamp meter - and while it does improve low level measurements, it is not always convenient,  especially when zeroing.

[bastl_r]

using the "zero" button
Once you have done this, do not change the orientation significantly. Otherwise you will immediately have a huge measuring error.

[beatman]

Extech 380942 30A True RMS AC/DC Mini Clamp Meter.

[csuhi17]

That doesn't look bad either.
benning cm 10-pv

[wofritz]

I recently found a current clamp meter that has a dedicated mA range and is still cheap (under 100):

<Peaktech 4350>

I have this one.  It is working quite well even in the DC mA range. Problem is zeroing. Best results are obtained if you zero it in the circuit and don't change the setup after that. But that's not possible if you can not switch off the device under test, which might be the reason to use a clamp meter in the first place.

[Hydron]

I think mA resolution and careful zeroing is about as good as you can do without going to heroic efforts to minimise the gaps in the magnetic circuit (as the multi-kilobuck tek/hikoi/clone probes do, to the extent of lapping the core interfaces and using thin film hall sensors and nulling coils). Even those ones are pushing it for use at sub-mA resolution.

[HKJ]

I decided to check my Benning CM11 with a current source (Keithley 2460).
Short-term it only changes about 0.1mA, i.e. measuring 0.5mA it changes between 0.5mA or 0.6mA, but boosting the current to 1A for a short time (Maybe 10sec) may add a offset of a few mA*, i.e. requiring a new ZERO to get the low current reading correct again.
*This kind of offset is due to magnetizing the clamp, i.e. it will only occur first time or after a current direction reversal, I did play a bit with some clamp meters and magnetization here: https://lygte-info.dk/info/DMMClampDemag%20UK.html

The CM11 is much better than the UT210e, but the Fluke is probably better in the lowest measurements.

[HKJ]

Which Fluke has better DC measurement parameters than the Benning CM 10-PV? for the same amount of money?

https://www.benning.de/products-en/testing-measuring-and-safety-equipment/current-clamp-multimeter/pv-current-clamp-meter-cm-10-pv.html

The Fluke was mentioned earlier in the thread, it is a special purpose clamp meter, not a general purpose one and is probably much more expensive from new, but can be bought used.

[csuhi17]

Which Fluke has better DC measurement parameters than the Benning CM 10-PV? for the same amount of money?

https://www.benning.de/products-en/testing-measuring-and-safety-equipment/current-clamp-multimeter/pv-current-clamp-meter-cm-10-pv.html

The Fluke was mentioned earlier in the thread, it is a special purpose clamp meter, not a general purpose one and is probably much more expensive from new, but can be bought used.

I may have misinterpreted the description of the Benning that I linked to, which is why I deleted my previous question.
If I managed to understand correctly, then a
The uA measurement does not apply to the clamp meter...
The clamp meter measures with a minimum scale of 10mA.

[HKJ]

I may have misinterpreted the description of the Benning that I linked to, which is why I deleted my previous question.
If I managed to understand correctly, then a
The uA measurement does not apply to the clamp meter...
The clamp meter measures with a minimum scale of 10mA.

Clamp meters measures the magnetic field around a wire and calculates the current from that, when measuring DC the earths magnetic field is a issue for low current measurements.

For that reason most clamp meters works with resolutions of 0.01A or worse, but there are a few meters with better resolution, many of them they are not really more precise and the extra digit is hard to get any reliable information from.

A few like the above Fluke and above Benning are made to really work at low current, the Fluke with 0.01mA resolution and the Benning with 0.1mA resolution. I do not know much above the Fluke, but the Benning can be used to see current a bit below 1mA (it requires careful use).

A few clamp meters has regular DMM shunt for low current measurement, the above do not, but uses the clamp.

[Martin72]

The Owon sounded so interesting to me that I ordered it and it should arrive tomorrow.

Actually arrived today.
I still have the UT210e, so it will be easy to compare.
First impression of Owon after unpacking:
Good touch quality, I wouldn't have thought.

[Martin72]

Clamp meters measures the magnetic field around a wire and calculates the current from that, when measuring DC the earths magnetic field is a issue for low current measurements.

It would be better if they were equipped with the current compensation method, which increases a current through a winding on the core until the difference to the measured current is 0.
These current clamps can then also be easily demagnetized; they have a corresponding function for this.
But unfortunately this is not feasible in such price ranges, perhaps the fluke in question has this in order to be able to measure so sensitively at all.
In any case, the Owon showed an "insane offset" when you switch to DC - I find over 300mA intense.
You can zero it with the "Zero" button, but that only conceals it.
I have now taken a few measurements, preferably in the lower mA range, pictures are currently being prepared.

[Martin72]

Here are a few measurements, which I will soon make a little more detailed (other currents, voltages, resistance, etc.), possibly in a new thread.

[csuhi17]

In any case, the Owon showed an "insane offset" when you switch to DC - I find over 300mA intense.

I have 6-1 of these, I could have left one
At 2A, I have an offset from -150mA to 600mA.
But the measurement is not affected.

[wasedadoc]

There are two quite different situations:

1.  The clamp meter is in a fixed position and the current can be turned off when zeroing.

2.  The current cannot be turned off, so the clamp meter must be in different places when zeroing and measuring.  Even worse is when the meter is being handheld.

[Kean]

I may have misinterpreted the description of the Benning that I linked to, which is why I deleted my previous question.
If I managed to understand correctly, then a
The uA measurement does not apply to the clamp meter...
The clamp meter measures with a minimum scale of 10mA.

Yes, it isn't at all clear from the CM 10-PV data sheet.  After looking at the user manual it shows the only range that uses the clamp meter is the Amp range.  All other measurements including the microamp range require using the probes.

As mentioned above the Fluke 771/772/773 clamp meters have a 10uA resolution but have a limited range to 110mA.  They are specialist meters for process control and priced accordingly.  The Kyoritsu 2500 is similar with 10uA resolution and max 120mA.  I bought my Fluke 771 many (~10) years ago, and apart from my Tek scope it was one of the most expensive pieces of test equipment I owned at the time.  I still have it and it still works fine.

The only handheld microamp resolution clamp meters I have come across are for AC leakage measurement, but there may be some specialist ones I haven't seen.  I have the UT251A which measures up to 60A AC, but has a resolution of 1uA.  I believe it is 6000 count, so max 6mA at that resolution.

The best way to do low current measurements with a clamp meter is to pass the wire being measured through the clamp multiple times, but that isn't always practical and still doesn't come close to the resolution you can get by inserting a current shunt into the loop.

I own a few of the UT210E clamp meters, but I find their readings are inconsistent.  One in particular needs calibration as it has a large offset that I can zero out but otherwise cannot remove even with careful degaussing.  I also have a couple of TENMA IN05268 clamp meters with a 1mA resolution, and while they are more expensive than the UT210E, they are my preferred DC clamp meters.

Yes, I own a few meters... 

[Martin72]

A few...

I have now compared the two with DMMCheck Plus.
The Owon not only has 20000 instead of 2000 counts, but also frequency measurement and duty cycle.
Neither of them can measure voltage with 10kHz AC.
But that's not what they are designed for.
Should I continue here or should I open a new thread?

[Kean]

Should I continue here or should I open a new thread?

I suggest continuing here.  A search will find the posts either way.

I will try do some similar comparisons later today of a few of my clamp meters against my Advantest R6142 and Keysight 34465A.

[HKJ]

Yes, it isn't at all clear from the CM 10-PV data sheet.  After looking at the user manual it shows the only range that uses the clamp meter is the Amp range.  All other measurements including the microamp range require using the probes.

I do not know about the CM10-PV meter, I only talk/write about the Benning CM11 meter.

As mentioned above the Fluke 771/772/773 clamp meters have a 10uA resolution but have a limited range to 110mA.  They are specialist meters for process control and priced accordingly.  The Kyoritsu 2500 is similar with 10uA resolution and max 120mA.  I bought my Fluke 771 many (~10) years ago, and apart from my Tek scope it was one of the most expensive pieces of test equipment I owned at the time.  I still have it and it still works fine.

Working low current DC clamp meters are expensive.

The only handheld microamp resolution clamp meters I have come across are for AC leakage measurement, but there may be some specialist ones I haven't seen.  I have the UT251A which measures up to 60A AC, but has a resolution of 1uA.  I believe it is 6000 count, so max 6mA at that resolution.

Measuring low AC current is not that hard, the earth magnetic field do not change fast, i.e. it do not affect AC measurements.

The best way to do low current measurements with a clamp meter is to pass the wire being measured through the clamp multiple times, but that isn't always practical and still doesn't come close to the resolution you can get by inserting a current shunt into the loop.

Using multiple turns in the clamp can make any clamp meter good at mA or even uA range with enough turns.
Measuring low mA or uA DC current with a clamp meter is not common.

I own a few of the UT210E clamp meters, but I find their readings are inconsistent.  One in particular needs calibration as it has a large offset that I can zero out but otherwise cannot remove even with careful degaussing.  I also have a couple of TENMA IN05268 clamp meters with a 1mA resolution, and while they are more expensive than the UT210E, they are my preferred DC clamp meters.

The UT210E is a fairly good low cost meter at low currents and one I will recommend for hobby usage, but if you really need to measure a few mA with a clamp meter, the Benning CM11 (or similar, like Fluke) is the answer.

Yes, I own a few meters... 

Who doesn't.

[Martin72]

I suggest continuing here.

OK...

Here is a table with the values, on the far left are the actual calibrated values from DMMCheck Plus.

I like the Owon better, currently.
It could be the successor to the UT210E as a low-cost clamp meter, with higher resolution and slightly more functions.

[DaneLaw]

If I recall the Owon CM2100/B had a tendency to drift alongside a heavy offset, and with a very barebone input protection close to non-existent, but that is Owon meters in a nutshell..
but like always with these cheap meters.. it can vary a lot from unit to unit and how lucky you are in that lottery.

but cheap clamp meters with 1mA DC resolution, are a dime a dusin these years and can be had for around 25 euro and up.
even AC+DC clamp units with 1mA DC & 0.1mA AC on the clamp is from 30 euro and up (incl. delivery and 25% EU VAT)
but none of them seems optimized for low current with a small gap/eye, so the performance will likely be around the norm, as we see with the likes of 210E & co.

[Martin72]

If you really need accuracy in the mA range, you unfortunately have to spend money, you can't have certain things cheaply.
I still like the Owon better than the Uni-T, but that shouldn't cloud the fact that we're talking about 40€ devices here.
I think you can expect something "serious" from the Benning onwards.

[BILLPOD]

Well Martin, at least you got batteries with yours   And I sprung for the model with Bluetooth, as I have a penchant for meters with it.   My comparison was not exacting as yours, but my UT210E and CM2100B ran neck in neck, always within a couple counts, (least significant digits).
I find the bluetooth app is better than most of my other BLE meters,
as it has multiple recording options.  I'm going to put my UT210E in the Owon pouch and keep it in my vehicle and keep the Owon on my bench,
or within easy reach. 

[Kean]

Sorry that I didn't get a chance to run these tests last year... but here are the results.

I've attached the spreadsheet of comparison data in PNG and CSV formats.  I skipped recording a few results where they were not meaningful.

For the Fluke 771 with currents below around 1mA it could take about 10 seconds to settle, but did a pretty decent job.

I ran the tests twice to verify they came back much the same.  I also experienced a power failure in the office while doing this, so I ended up having to redo half of it a third time.  I tried not to move anything, but I am sure there was some drift during the hour this all took.

Forgot to mention here, that the current source was my Advantest R6142.  Also, none of my gear has recent calibration - but my 34465A, 34401A, and 34972A all agreed within a few counts when last compared.

Happy New Year!

[Martin72]

Thank you, it could hardly be any clearer...
Then I'll test the Benning CM11 at work next week.

[Martin72]

Well Martin, at least you got batteries with yours

And a screwdriver !

[Kean]

Thank you, it could hardly be any clearer...

I was a bit surprised at the final results in the 1-5mA range, as I didn't expect them to read so close to the actual value.  I did have to re-do the zero a couple of times to get them stable at the start, and again when they did an auto power off twice mid-way through all the measurements.

My UT210E #1 device has a note on it that it was not reading stable values when I used it in early November, but it came good after cycling the range switch a few times.  The other two UT210Es have a note that they read low, which matches the results.  I bought these UT210E's on ebay from a Chinese seller back in 2017.

ST-337 #1 (aka TENMA IN05268) has been my go-to clamp meter.  I hadn't noticed that ST-337 #2 was also reading more than 10% low.  I bought these both from Element14, one in 2009 and the other in 2012.  From the serial numbers, it looks like #1 is actually the older one.  These each cost more than all three of the UT210Es.

I can't find a record, but it looks like I probably bought the Fluke 771 back in 2008 at the RS trade counter.  That would make sense as 2008 is when I started doing my electronics consulting business.  Back then it would have cost close to 20x the price of a single UT210E bought nearly 10 years later, and is still at roughly the same multiplier now.

If the Benning CM11 was available in Australia, and was available for less than 10x the cost of a UT210E, then I might consider getting one of those as well.   

[BILLPOD]

I got the screwdriver, but no batteries, which is no biggie, as they are probably junk alkaline that would leak and ruin the meter.  I put in a pair of Nimh, but I don't think they will last long, as supposedly the meter cuts out at 2.2 volts.  I am considering lithium primaries, but wonder how the higher voltage will play out

[Kean]

The OP hasn't replied at all, so I'm wondering if they got the answer they were after... or just have more questions...

They've been active on the forum since starting this topic, and even the last few posts, but not actually posted anything new.

[KlausF]

After 2 years, my UNI-T 210E suddenly does not function any longer, DC amps is defective, I would say for no reason. It was rarely used and if it is was, then only indoor and for low currents. Cheap Owon CP2100 looks like UT210E, I want something better. Any suggestions ? What would be a good alternative for let´s say up to 400 bucks ?
I was about to get me a Benning CM 11, but its "performance" is not what I am looking for.

[HKJ]

After 2 years, my UNI-T 210E suddenly does not function any longer, DC amps is defective, I would say for no reason. It was rarely used and if it is was, then only indoor and for low currents. Cheap Owon CP2100 looks like UT210E, I want something better. Any suggestions ? What would be a good alternative for let´s say up to 400 bucks ?
I was about to get me a Benning CM 11, but its "performance" is not what I am looking for.

I have not looked at the video, but in my experience it is way better at low current then the 210E (I have both).
For clamp meters I have two groups: Low DC current and general purpose. CM11 wins in low DC current, but for general purpose it lacks high current ranges. Because I work with electronic I mostly need low DC current measurements, this makes CM11 my favorite clamp meter.

[Martin72]

I have not looked at the video,

I looked at it, a bit hair-raisingly done...
The biggest disadvantage of the CM11 is that you have to be very careful not to overrun it in terms of current.
If you keep this in mind, it is very suitable for small currents.

[HKJ]

I have not looked at the video,

I looked at it, a bit hair-raisingly done...
The biggest disadvantage of the CM11 is that you have to be very careful not to overrun it in terms of current.
If you keep this in mind, it is very suitable for small currents.

I have still not looked at it, but if the issue is that the clamp get magnetized at higher current, I do not see that as a serious issue.
I played a bit with it here: https://lygte-info.dk/info/DMMClampDemag%20UK.html

[Martin72]

First, a mixed current is measured (direct rectification without an electrolytic capacitor) and it is wondered why the display jumps back and forth.
Then at some point the CM11 is connected between a load and the supply and it is criticized that it is reasonably accurate - with regard to the values displayed at the load and the supply and other errors.
A somewhat adventurous "review".

[J-R]

I say the video points out the differences between someone who is coming from the concept side vs. someone who is just trying to do a job and measure an unknown with their clamp meter.  So yes, some of the tests and conclusions are a bit questionable in the context of this thread, but you may still bump into those conditions in the field.  Who is right?  Maybe one solution is high-speed sampling, then perform any desired calculations such as averaging.

The bugs and lockups are disturbing though, especially at that price point.  They should have gotten a second unit to rule out a faulty device for some of the issues.

Overall, it's not looking too good for the CM11.  Limited functions, bugs/lockups, expensive...  But maybe some would still buy it for specific tasks.

[Martin72]

The bugs and lockups are disturbing though, especially at that price point.  They should have gotten a second unit to rule out a faulty device for some of the issues.

What bugs ?

One of the main problems is that you have to know what you are using what for.
For me, the matter was over when PWM signals or the simulation thereof were measured.
But that is beside the point.
We bought this current clamp because we wanted to measure small standby currents.
Before we could use this current clamp, we had to have it calibrated externally and the second one has now successfully passed this type of calibration.
I therefore only see two possibilities.
Either the video is largely rubbish, or the calibration carried out according to international standards is rubbish.
Due to the principle, I tend towards the former.

[J-R]

The bugs and lockups are disturbing though, especially at that price point.  They should have gotten a second unit to rule out a faulty device for some of the issues.

What bugs ?

Enter manual range mode, can't go back to automatic.  You have to turn it off and back on.
There is no display icon to indicate if you are in manual or automatic mode.
Min/Max function has various issues, such as showing OL when you open the clamp/stop current flow while in manual mode and it actually locks up the meter if you press hold while using Min/Max.
It generates a 102Hz signal back through the wire being tested while in DCA mode.
Over 30mA draw in DCA mode, which combined with the two AAA batteries means a very short runtime (maybe 30 hours).

I agree with you about the the flaws in the video.  They clearly don't understand a lot about what they are doing.  The point I was trying to make was all they know is when they try to take certain measurements, one cheap clamp seems to work and the CM11 doesn't.

[beanflying]

Looking for a cheapish DMM to leave in the Car toolbag so I was going to buy another 210E as I like the one I already have but the BT version of the Owon for singlehanded vehicle work might be handy and make for a decent second clamp meter if needed.

Anyone got a BT version care to comment? Yes I know BT has issues too but it is what it is.

[naiclub]

I use model 204A and it works well and is quite accurate. Used for almost 10 years.

[BILLPOD]

Anyone got a BT version care to comment? Yes I know BT has issues too but it is what it is.

I have recently acquired the OWON and have been comparing it with my 210e, and they are pretty much equal in accuracy, (DC current is all I  have been comparing).   However, the Owon has the bluetooth, which I love, and the android software is nice to use.   But, as with the bluetooth on any of my other meters, the range is poor, but better than my Mooshimeter.

[mzzj]

You really do have to consider ALL external sources of magnetic fields, but developing a technique and using the "zero" button has proven to give reasonably repeatable measurements.

Just tested out of curiousity the effect of current-carrying wires outside of the jaws: (Owon CM2100)

Conductor carrying 20A current causes visible 2mA error if closer than apprx 100mm to clamp end. If placed next to jaw opening the error is up to 50mA. Something to keep in mind if working in a crowded electrical cabinet or car wiring harness.

[Kean]

I use model 204A and it works well and is quite accurate. Used for almost 10 years.

This topic is about "clamps meter for low DC currents" and the OP was asking about "mA and uA" measurements.

The UT204A has 40A and 600A ranges.  So the UT204A is not really applicable... unless you know something we don't...

[HKJ]

Just tested out of curiousity the effect of current-carrying wires outside of the jaws: (Owon CM2100)

Conductor carrying 20A current causes visible 2mA error if closer than apprx 100mm to clamp end. If placed next to jaw opening the error is up to 50mA. Something to keep in mind if working in a crowded electrical cabinet or car wiring harness.

That is good, 0.01% error at 10cm is not much. In praxis you would not have 20A next to a clamp measuring mA. Except if you want to measure sensitivity, or you are a bit stupid (Sorry, but that is my opinion).

I have not seen any errors on the CM11, but I only use it to measure low DC currents (That was what I bought it for and it do it very well).

[J-R]

I have not seen any errors on the CM11, but I only use it to measure low DC currents (That was what I bought it for and it do it very well).

Can you check your CM11 to see if it has the same issues as the one in the video?

[mzzj]

Just tested out of curiousity the effect of current-carrying wires outside of the jaws: (Owon CM2100)

Conductor carrying 20A current causes visible 2mA error if closer than apprx 100mm to clamp end. If placed next to jaw opening the error is up to 50mA. Something to keep in mind if working in a crowded electrical cabinet or car wiring harness.

That is good, 0.01% error at 10cm is not much. In praxis you would not have 20A next to a clamp measuring mA. Except if you want to measure sensitivity, or you are a bit stupid (Sorry, but that is my opinion).

You don't always have the luxury of not having current carrying conductors next to clamp measuring mA's, ie previously mentioned car wiring harness.

And some other clamp meters are behaving lot worse:
Fluke 301D gives 0,3A error when jaws are next to conductor carrying 20A current. 6 times worse than the mentioned Owon.
Found out this accidentally in the calibration lab as 301D calibration results were all over the place compared to typical current clamps.

[LeonR]

Just a heads-up: Owon skimped on the protection side of the CM2100/B when compared to the original model (Uni-T UT210E). I posted a video on the CM2100 topic: https://www.eevblog.com/forum/testgear/owon-cm2100b-is-uni-t-ut210e-inspired/

[DaneLaw]

Just a heads-up: Owon skimped on the protection side of the CM2100/B when compared to the original model (Uni-T UT210E). I posted a video on the CM2100 topic: https://www.eevblog.com/forum/testgear/owon-cm2100b-is-uni-t-ut210e-inspired/

No you didnt -  you more like reposted the exact same video that was posted months earlier in 3 posts above yours, even with a direct timestamp to the relevant circuit parts..
and where OP are even talking about the lack of protection after watching that exact video posted months earlier, but all that seemed to go over your head.?

[DaneLaw]

A relatively cheap AC+DC clamp meter I have been puzzling about for the last ½ year is the Winapex 268B
- as it seems to have the current tolerances from Unit-T211B on the clamp with 0.1mA in AC and 1mA in DC while costing around 1/3 of the UnitT- UT211B.

Anybody tried one of these 268B ? - the price seems to be around 35€ [incl. VAT & delivery]






built-in battery (750mAh)  https://ae01.alicdn.com/kf/A1e8c66d9c3e34135b4e6c7ac5177fd0c2.jpg   & https://ae01.alicdn.com/kf/A40b01b1364e84150a4aaf693002f709f9.jpg

[Martin72]

I consider only 2% tolerance in the 60A range to be unbelievable.
As a rule, current clamps of this type are less accurate with increasing current.
In addition, there is this strange "roller coaster" of tolerances in the ACA range.
1.5%, then 2.5%, then back down to 2%.
It's tempting to buy and test them.

[Bobson]

APPA MA3 and MA5 have 1mA +- 1.8%+5D resolution according to specs. Dunno if they are available under Mastech, Benning or other label.

[techneut]

I consider only 2% tolerance in the 60A range to be unbelievable.
As a rule, current clamps of this type are less accurate with increasing current.
In addition, there is this strange "roller coaster" of tolerances in the ACA range.
1.5%, then 2.5%, then back down to 2%.
It's tempting to buy and test them.

I just ordered one from Banggood for €36. Just to see....

[Martin72]

Here are the (photographed) results from the CM11 during the last calibration.

[MathWizard]

I hardly ever use current measurements, (although my meters use currents for resistance measurements too) and in a lot of cases, I'd trust that less than some voltage measurement, but yeah then I'm probably going to use some some measured resistance anyways and Ohm's law....

But yeah how trustworthy are good DMM's or pico-ampmeter's at stuff like measuring input bias currents to op-amps ? I have a good book to read on precision measurement techniques, I need to read more...
https://download.tek.com/document/LowLevelHandbook_7Ed.pdf
https://www.ti.com/lit/ml/slap103/slap103.pdf

[jackobo]

I recently found a current clamp meter that has a dedicated mA range and is still cheap (under 100):

<Peaktech 4350>

I have this one.  It is working quite well even in the DC mA range. Problem is zeroing. Best results are obtained if you zero it in the circuit and don't change the setup after that. But that's not possible if you can not switch off the device under test, which might be the reason to use a clamp meter in the first place.

Need one for possible car battery current leak detection, what do think would 4350 model fit for this purpose?thanks

[ball]

Do any of these default to DC current and continuity?