Good clamp ammeter? - Page 1
Forum section: electronics / general

author: tom66
author_rank: Super Contributor
timestamp: May 27, 2012, 07:58:27 pm
content: I'm looking for a good clamp ammeter to measure AC (non linear, i.e. non-PFC bridge & cap) and DC currents above the 10A my BK Precision 2709B supports. Maximum current is not that important, 100A at most is fine, and accuracy is not crucial.I've been eyeing up the UT204 for a while now, especially as it has true RMS capability and is under £40 shipped (max budget £50.)http://www.ebay.co.uk/itm/Brand-New-UNI-T-ACA-DCA-Digital-Clamp-Meters-with-True-RMS-UT204-/190664178344?pt=LH_DefaultDomain_0&hash=item2c64787aa8#ht_1348wt_1189I won't use the voltage measurement above about 20V (if at all), so I'm not too worried about safety there - I have my BK meter which has nice MOVs on the inputs for measuring mains level voltages.However, I'm thinking now that I have a digitising scope with ac rms and dc rms calculation options and seeing the actual waveform would be very useful and helpful in my studies and repair of power supplies. Does any manufacturer produce a clamp on current probe which can plug into a BNC at a decent price - I mean, I can see a few Fluke ones but they start at £200 so way out of my budget.Perhaps it's possible to mod a cheap clamp meter (capable of DC as well as AC, hall effect measurement not just a current transformer) to get a signal out which would then be sent to the scope - but I would imagine having a BNC sticking out the side of a meter would introduce some safety hazards, potentially blowing the scope/DUT up if there's a voltage on the common terminal.Any inputs appreciated!

author: SeanB
author_rank: Super Contributor
timestamp: May 27, 2012, 08:11:25 pm
content: If you are going to do this with a meter then it would be best to disable the voltage inputs totally, and feed the probe cabling out through one of the holes. This then would be a probe only meter. If you are going to do AC only at lowish frequency ( less than around 20kHz, then get a cheap clamp meter, and rip out all the internals, and just use the current coil in it, with a suitable load resistor, to drive the cable directly.

author: T4P
author_rank: Super Contributor
timestamp: May 28, 2012, 02:54:16 am
content: you really think UNI-T products are dangerous ? People buy the UT204 and are not afraid

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 28, 2012, 06:31:47 am
content: Quote from: tom66 on May 27, 2012, 07:58:27 pmforget ut204 if you want to measure low (up to 100A), its for industrial with1000shigher of amperage, might have problem measuring low A, get UT202, cheaper and i have one. used to measure/characterize mains supplied households, i still liveUT202 got temp measurement but instead no Freq/duty as in UT204. YMMV.... DC current? now there's the problem. cheapo clamp type device cant measure that just easily, you need hall-effect clamp iirc.

author: T4P
author_rank: Super Contributor
timestamp: May 28, 2012, 10:12:42 am
content: Quote from: Mechatrommer on May 28, 2012, 06:31:47 amYeah ... UT204 does up to 400amps same goes for the UT203 but that's it.it's the DC that makes the mark.

author: BravoV
author_rank: Super Contributor
timestamp: May 28, 2012, 11:02:16 am
content: Too bad its beyond your budget, its Agilent clamp meters, they're capable of measuringDC and also DC + AC currentup to 1000 A.Did a tear down on my U1213A while ago ->https://www.eevblog.com/forum/product-reviews-photos-and-discussion/agilent-u1213a-clamp-meter-teardown-short-video-review/

author: tom66
author_rank: Super Contributor
timestamp: May 28, 2012, 11:21:03 am
content: Well, the UT204 measures in the lowest range at 40A, at 4000 counts that is 10mA resolution, which is fine for my purposes. Accuracy isn't stellar... At the moment I'm a poor student and can't afford any high priced gearI'd love to get a Fluke or Agilent probe but I can't afford one.

author: Kilroy
author_rank: Regular Contributor
timestamp: May 28, 2012, 03:42:26 pm
content: You could try to pick up a Fluke 36 off Ebay. Good, solid, accurate true RMS meter. AC current to 660A and DC current to 1000A. There are a few on Ebay now.I'd much rather pay ready money for a good used Fluke 36 than taking a flyer on one of those brand new cheap clamps, but that's just me.

author: bdivi
author_rank: Regular Contributor
timestamp: May 29, 2012, 12:24:16 pm
content: I have had for years a Mastech MS2102 that covers pretty much what you need AC and DC current to 10mA, voltage and ohms and it is very compact and rigid.Overall happy with it.Cheers

author: darrylp
author_rank: Regular Contributor
timestamp: June 03, 2012, 08:21:38 pm
content: i've got a UT204, seems fine. couple of tests at low amp's ( under 6 amps ) and its accurate to 50mAgreat having AC and DC clamp current. i keep it in my automobile all the time.for the money a good meter i reckon.Sent from my Transformer Prime TF201 using Tapatalk

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: June 04, 2012, 10:13:46 am
content: It may be just me, but when it comes to measuring high voltages, currents and anything in CAT II range, i do only trust instruments from a manufacturer that got a good product support unit. And most for my own safety, do have a reputation on taking MY safety in a serious way..And by that i mean that they are big enough to stand by their products by being responsible enough to recall products that in retrospect are found unsafe or have an issue..Like Fluke..http://www.fluke.com/fluke/usen/support/safety/default.htmWhen even Fluke can do errors, with their backing of knowledge and research, the others must have isuses, but strangely they don't address them. This is setting us users in danger..Other companies that don't tell about their in retrospect bad products i don't trust, simply as that.But i don't see that UNI-T got any recalls whatsoever on their webside, or in a goggle search.. i may be wrong but such a manufacturer i don't trust.. and the funny thing is that my insurance agent agree with me there!But that is my point of view..

author: T4P
author_rank: Super Contributor
timestamp: June 04, 2012, 01:06:35 pm
content: Unless ...Well, people now avoid ANYTHING except the clampmeters and the UT61x (not including UT60) and also a few other low end onesThe... how do you die from a clampmeter being clamped onto a wire i don't know how

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: June 04, 2012, 04:25:49 pm
content: Quote from: DaveXRQ on June 04, 2012, 01:06:35 pmThat's easy, You trust Your meter, and measure Zero amp or volts.. and You touch the wires.. all due to as Fluke had a defective product.From Fluke recall on 33X claps..:Description of the problemThrough quality assurance tests, we have discovered a potential short circuit connection on the circuit board. This may lead to inaccurate voltage readings including alow or no voltage reading on a circuit energized with a hazardous voltage. This finding could create a hazardous situation if theuser were to contact live voltage based on an erroneous instrument reading.

author: T4P
author_rank: Super Contributor
timestamp: June 04, 2012, 04:34:32 pm
content: But at least i don't have problems with a UNI-T product do i ?

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: June 04, 2012, 04:42:34 pm
content: Who know what problem You could have with it..But do you find any recalls for any UNI-T meter or product?So if not, are they perfect and don't make any bad product..Or do they just keep the problems for them self?So who do you trust your life with.. el cheapo or a well reputaded and solid company that are honest about any safety risks..I know what i do.. the rest is up for yourself to do the deeper thinking about.

author: T4P
author_rank: Super Contributor
timestamp: June 04, 2012, 06:41:46 pm
content: El cheapo and probably trusted ... Hey, does anyone even complain of a UNI-T clampmeter? UT61x ? I don't think so

author: tom66
author_rank: Super Contributor
timestamp: June 04, 2012, 07:04:13 pm
content: There are absolutely no safety risks involved with what I am doing; I will be measuring, characterising and repairing supplies. I always disconnect power to the supply before getting out the soldering iron, I would think that is common sense. I think I'm going for the UT204A because DealExtreme have it for 30 of my British pounds, which fits my budget nicely.

author: bdivi
author_rank: Regular Contributor
timestamp: June 05, 2012, 05:11:16 am
content: Quote from: tom66 on June 04, 2012, 07:04:13 pmThe fact you think there is no risk is already a major risk !Although I see very little danger in using a clamp meter, messing around with power supplies is not just 'always disconnect' and 'common sense' matter.

author: T4P
author_rank: Super Contributor
timestamp: June 05, 2012, 06:14:09 am
content: Quote from: tom66 on June 04, 2012, 07:04:13 pmThey only have the 203 not the 204 which isn't TRMS but aliexpress has it for not much more

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: June 05, 2012, 11:18:56 am
content: Quote from: bdivi on June 05, 2012, 05:11:16 amYes, that`s a dangerous view of things.As i diver, i have meet a lot of different divers around the world. They always pair the most experienced with the least experienced.That is the attitude that's kills divers, not thinking true all the risks, lack of experience and nothing bad has happend so far..And DaveXRQ, please know..But with age comes knowledge, But first, you got to make it and survive to become older.. before that its just to take advice from the ones that already have some experience.But if you feel comfy with what you do, and thinking first- doing later, that's fine. We just want the best for you and advice you the best we can.

author: T4P
author_rank: Super Contributor
timestamp: June 05, 2012, 02:53:17 pm
content: I always take things with a tablespoon of salt. I do not even trust the CAT III rating on my UT61E if you ask meAnd of course i had held a meter that blew up in my hand so don't say i do not hold any wisdom

author: tom66
author_rank: Super Contributor
timestamp: June 06, 2012, 08:16:50 am
content: Quote from: bdivi on June 05, 2012, 05:11:16 amI realise that I worded my post wrong - I am talking about there being little to no risk with how the meter will be used, in that I will be using the voltage measurement up to about 20V and the current measurement will be for characterisation and debugging only. Of course there will be a risk with any power supply repair. I've repaired 22 LCD TVs so far, and just recently I had an exploding NTC thermistor and fuse go after me. And after that I figured the filter cap would have been discharged - couldn't have been more wrong, so that was painful.

author: T4P
author_rank: Super Contributor
timestamp: June 06, 2012, 12:06:05 pm
content: I always take my big phillips screwdriver to a cap - charged or not

author: tom66
author_rank: Super Contributor
timestamp: June 06, 2012, 01:45:20 pm
content: I'm looking at the UT204A not the UT203.http://www.dealextreme.com/p/uni-t-ut204a-1-5-lcd-digital-clamp-multimeter-1-x-9v-6f22-127969I also like the temperature probe. I have an IR temp probe, but it would be useful to have a thermocouple style probe too.No need for the capacitance (my BK goes to 66mF) and I have an ESR meter. One thing I would like is an LCR meter, manual ranging is fine, but has to measure inductance done to µH, and most cheap manual ranging jobs don't.

author: T4P
author_rank: Super Contributor
timestamp: June 06, 2012, 05:30:48 pm
content: OopsIf you want a great LCR meter the Mastech MS5308 from precisegauge.com is a nice dealWell actually anyway if anyway is after a proper temperature meter a DMM's temp measurement is usually not that great in any sort.