Usefulness of clamp meter for general electronics work?

[Rooster Cogburn]

I've been looking at clamp multimeters for general electronics work. Consumer electronics troubleshooting (TVs/network gear/audio gear/laptops/game consoles), PC/microcontroller/RPi stuff. Clamp multimeters seem to be mostly targeted towards electricians, car mechanics, high amperage AC measurements, but I wonder if I would get some utility out of one on my bench.

I did some research and stumbled on the UT210E (Pro) as an inexpensive AC/DC current clamp meter with mA resolution and read a bit through the large thread it has here. There's also the slightly more expensive UT204+, but I guess 6000counts with a 6A range is basically the same as 2000counts with a 2A range if I'm mostly interested in mA?

I'm just curious if you think it's worth the 30-60EUR to buy such a meter for my use case, considering the limits in accuracy and potential finicky issues with interference, zeroing and magnetized clamps. Also, would looking into a current scope probe or a clamp for my existing Fluke meter be a better option? (I suspect no since it'll likely be too pricey, but please correct me there).

Thanks!

[Fungus]

I'm just curious if you think it's worth the 30-60EUR to buy such a meter for my use case

I vote "no".

[Rooster Cogburn]

I vote "no".

I'd get some use out of some magic device that could tell me the current flow through a wire, but these inexpensive ones are just too low accuracy to be of use?

There seem to be inexpensive current clamp scope probes:

https://www.aliexpress.com/item/1000002327012.html

...but >=10mA and ±(1.5% ± 5mA) is not very useful.

I've also found this device:

https://www.kew-ltd.co.jp/en/products/detail/00039/

The 0.01mA DC resolution and smaller clamp seem very much like what I'm looking for, but I don't even dare to research its price.

[Grandchuck]

This is an interesting device:

https://www.crowdsupply.com/weston-braun/little-bee

[Rooster Cogburn]

This is an interesting device:

https://www.crowdsupply.com/weston-braun/little-bee

Huh, neat. I know there are scope probes that you can just put on a PCB trace, but they're usually way out of my price range and much more expensive than this.

[HKJ]

I've been looking at clamp multimeters for general electronics work. Consumer electronics troubleshooting (TVs/network gear/audio gear/laptops/game consoles), PC/microcontroller/RPi stuff. Clamp multimeters seem to be mostly targeted towards electricians, car mechanics, high amperage AC measurements, but I wonder if I would get some utility out of one on my bench.

Depends on what you need. A clamp meter is very useful when you want to measure current with minimal burden voltage, but they are not very good at low current.
My favorite clamp meter is Benning CM11, it is considerable better than UNI-T at low DC current and low DC current is what I need most for electronic.
Note: With clamp meters low current is mA, they cannot be used at uA level.

[SilverSolder]

The Uni-T is good down to about 10mA or so.  It definitely has its uses - it is convenient in many cases when you don't need super high accuracy - but shouldn't be your only meter...

[Rooster Cogburn]

The Uni-T is good down to about 10mA or so.  It definitely has its uses - it is convenient in many cases when you don't need super high accuracy - but shouldn't be your only meter...

I got a Chinese Fluke already. It's OK, but it doesn't have RMS, bargraph and the continuity tester is slow. What to upgrade first... In any case, I'd buy the clamp meter for nothing but contactless current measurement.

Depends on what you need. A clamp meter is very useful when you want to measure current with minimal burden voltage, but they are not very good at low current.
My favorite clamp meter is Benning CM11, it is considerable better than UNI-T at low DC current and low DC current is what I need most for electronic.
Note: With clamp meters low current is mA, they cannot be used at uA level.

I've seen the meter you mentioned, but that's like 10x my budget. For me it's just that when troubleshooting and repairing stuff inserting a DMM into the circuit for current measurement is always a pain and I often though it would be nice to just measure if maybe the current going to that board or component was high. I'm not sure if the UT210E is precise/reliable enough, though. The drift and the limited resolution etc. I also wonder how often external magnet fields will prevent taking a measurement. I'm thinking of transformers in power supplies and I also often work on CRTs with all the magnetism from the deflection system.

[HKJ]

Depends on what you need. A clamp meter is very useful when you want to measure current with minimal burden voltage, but they are not very good at low current.
My favorite clamp meter is Benning CM11, it is considerable better than UNI-T at low DC current and low DC current is what I need most for electronic.
Note: With clamp meters low current is mA, they cannot be used at uA level.

I've seen the meter you mentioned, but that's like 10x my budget. For me it's just that when troubleshooting and repairing stuff inserting a DMM into the circuit for current measurement is always a pain and I often though it would be nice to just measure if maybe the current going to that board or component was high. I'm not sure if the UT210E is precise/reliable enough, though. The drift and the limited resolution etc. I also wonder how often external magnet fields will prevent taking a measurement. I'm thinking of transformers in power supplies and I also often work on CRTs with all the magnetism from the deflection system.

It is not a cheap meter, but it is better than UT210E for low current DC, for me that makes it worth the money.
For a cheap clamp meter used at low current DC the UT210E is good, the CM11 is the next step up, but it cost money.

[SilverSolder]

[...] For me it's just that when troubleshooting and repairing stuff inserting a DMM into the circuit for current measurement is always a pain and I often though it would be nice to just measure if maybe the current going to that board or component was high. [...]

I would say the Uni-T is perfect for that, as long as the device being troubleshooted? troubleshot?   ...uses more than 10mA - 15mA or so.   It is challenging to get good measurements at lower currents than that.

Sometimes it is possible to loop the wire carrying the current a couple of times through the clamp, which increases sensitivity commensurate with the number of turns...

[Bobson]

Do not forget that like many clamp DMMs, UNI-T 210e has very narrow bandwidth (not only TRMS).
When you speak about electronics lab use, do you consider that many low-cost DMMs, including Zotec/Aneng/etc have considerable sensitivity drop after 1KHz? It makes them unsuitable for many tasks.

[J-R]

It's not necessarily sold for this purpose, but if you're willing to pay a bit more or wait for a good deal to come along, check out the Fluke 771 for high accuracy, low DC current situations.
1mA accuracy is a piece of cake but it can also reach down to to the 0.01mA level. For example, I just did a quick test and got 15.47ma from my DMM and 15.49mA on the Fluke 771.

[Rooster Cogburn]

I would say the Uni-T is perfect for that, as long as the device being troubleshooted? troubleshot?   ...uses more than 10mA - 15mA or so.   It is challenging to get good measurements at lower currents than that.

Sometimes it is possible to loop the wire carrying the current a couple of times through the clamp, which increases sensitivity commensurate with the number of turns...

Troubleshat

Yeah, I think I could have some use for this device then. Read about the looping trick, it's a clever idea. I wonder if this would be useful for my CRT repairs as well...

btw, there is no meaningful difference between the normal and 'Pro' version, right? I think on AliExpress it's basically just Pro while I can buy a non-pro locally for the about the same price.

Do not forget that like many clamp DMMs, UNI-T 210e has very narrow bandwidth (not only TRMS).
When you speak about electronics lab use, do you consider that many low-cost DMMs, including Zotec/Aneng/etc have considerable sensitivity drop after 1KHz? It makes them unsuitable for many tasks.

I was mostly thinking about DC current and even my main DMM isn't a true RMS one, hm. To be honest, I have pretty much resigned myself to the fact that with any electronics bench equipment I'll either massively overspec 'just in case I might need that' or find out 6-18 months down the line that it's missing some feature or is lacking in performance. I'm very much still learning and it's basically safe to say that I don't know what I don't know and eventually will realize I need something a little different.

It's not necessarily sold for this purpose, but if you're willing to pay a bit more or wait for a good deal to come along, check out the Fluke 771 for high accuracy, low DC current situations.
1mA accuracy is a piece of cake but it can also reach down to to the 0.01mA level. For example, I just did a quick test and got 15.47ma from my DMM and 15.49mA on the Fluke 771.

About 10x my budget! For that kind of money I'd upgrade my main DMM to something like an 87V, buy a nice LCR meter, maybe an in-circuit ESR-meter and still have leftover money for a UNI-T clamp meter :-)

[maxwell3e10]

I use UNI-T 210E frequently for testing DC current in circuits. If one is careful, it is possible to get a few mA resolution. Just need to zero the meter, then slip the wire into the jaws without moving anything else or changing the orientation of the meter. It's a good compromise of accuracy, convenience and price. If I  need more precise current monitoring I solder a few ohm resistor into the line and measure the voltage.

[David Hess]

I use my clamp meters when doing electrician stuff, but never on my workbench for electronics.  I am more likely to use a kill-o-watt meter.

There is an exception.  I have a Fluke DC clamp meter which plugs into another multimeter and has milliamp resolution.  That comes in handy sometimes.

[beanflying]

My UNI-T gets pulled out for quick checks of AC and DC currents on my R/C gear or any mains gear I want to see if it is in the ballpark so yep it is worth the few $. That said while accurate for more serious or accurate measurements I pull out the shunts and loggers or better meters and break into the circuit. Compared to built in current ranges on most meters external shunts make a lot of sense but that is another can of worms for another topic but in testing them against the UNI-T it stacks up well.

For safety, speed and generally a good result buy it.

[radiolistener]

UT210E is must have if you're want to test current consumption for a powerful devices like 20-60 Amps, for example power amplifier, etc.

[Fungus]

I'd buy the clamp meter for nothing but contactless current measurement.

Use will be very limited at the currents you'll be measuring in the cases mentioned above.

Depends on what you need. A clamp meter is very useful when you want to measure current with minimal burden voltage, but they are not very good at low current.

At low currents the burden will be in the millivolt range so there's no real advantage.

If you're building stuff on the bench then it's fun to put something like this in the circuit: https://www.ebay.com/itm/321455179817

This lets you do a quick/safe check on the current without swapping the leads on the multimeter.

For that kind of money I'd upgrade my main DMM to something like an 87V

I wouldn't, not when Brymens are about 1/3 of the price and more capable. Leave the 87V for corporations with too much money.

[radiolistener]

If you're building stuff on the bench then it's fun to put something like this in the circuit: https://www.ebay.com/itm/321455179817

That's a bad choice, because 0.1 Ω at 60 Amps will have Voltage drop 6 Volts which is not acceptable.
And 60*6=360 W heating exceeds 10 W power rating for this resistor, so it probably will be damaged.

Also, often there is no way to break wire for current measurement and clamp meter is the only way you can use.

[Fungus]

That's a bad choice, because 0.1 Ω at 60 Amps will have Voltage drop 6 Volts which is not acceptable.

Common sense should say "Don't do this at 60 amps"...

OP said: "mostly interested in mA" so you could even use a 1 Ohm resistor - burden will be millivolts and you don't have to multiply the reading by 10.

[SilverSolder]

Here's another trick you can do with the little Uni-T:   measure currents up to 200A!

I ran into the problem of needing to measure the current of a starter motor, and the 100A range of the Uni-T was not enough...

To double the range, you can insert a "calibrated piece of wood" to hold the clamp open, creating an air gap in the magnetic circuit!

The gap needs to be 6.25mm wide (at least on my example) to cause the sensitivity to drop by half - so 100A on the display means 200A actual current!

[madires]

I use a clamp meter for measuring higher currents and when I don't want to cut or disconnect a wire. In general, if you deal with currents below 100 mA a DMM is clearly the better tool.

[Rooster Cogburn]

So I bought one, seems useful enough for 39EUR. I'll also eventually get a current clamp for the scope. Should be useful for buck/boost/SMPS work. I should try hooking up one of those hall effect sensor modules...

Makes sense that you can extend the current measurement range by opening up the ferrite core. Probably not something I'll need much, 100A is plenty for my purposes.

[BeBuLamar]

I wonder why would you need the clamp at all?

[beanflying]

I wonder why would you need the clamp at all?

Poking around in mains powered anything it is way safer and faster than bodging a DMM in circuit for a start. This is really the primary use case.

On the bench with low current (say less than a few Amps) a DMM for DC work in particular makes more sense.

In one of my use cases for R/C aircraft and Helis I can drop the clamp over a LiPo wire instead of finding room for a high power shunt and DMM or Logger. Typical currents here are anything from a few Amps toward 100A and can be over.

Because of the ability to measure DC current anything Automotive these work great, same non bodge benefit as witth mains and if you want to poke around an Alternator then way more capable than a DMM without an external shunt.