Do there exist clamp on type amp meters for small wires and currents  ? - Page 1
Forum section: electronics / general

author: Milacron
author_rank: Contributor
timestamp: August 27, 2011, 02:15:34 am
content: Similar to below but really small and good for reading DC currents as small as 40 milli amps ?

author: PeterG
author_rank: Frequent Contributor
timestamp: August 27, 2011, 02:47:58 am
content: I am thinking there would be a reasonable chance of reading 40mA AC, but i question 40mA DC. There would be an issue with ambient/background emf.Therefore, if it does exist, it will be expensive.Regards

author: grenert
author_rank: Frequent Contributor
timestamp: August 27, 2011, 03:18:44 am
content: It's not portable and it's ancient, but the old HP 428B will do what you're looking for.

author: Kozmyk
author_rank: Regular Contributor
timestamp: August 27, 2011, 04:52:16 am
content: Googling "low current DC clamp meter" or "small wire DC clamp meter" brings up a lot of units with 1mA resolution DC. Prices vary but none of them are the cheapest in their makers ranges. Most over $100 US.I've just bought a cheap one for rough/quick measurement of battery charging currents.Mastech MS2108A DC ranges 40A, 400A.Not quite what you're after.Cheap though, £33 posted.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 27, 2011, 05:10:51 am
content: Yes the pricing of the banded-trusted ones are about 180$ - 300$.At the same price are the ones for 0- 40A - 400A or more.Its like telling to you, that you need to come close to this price level,and get a low current or high current version.I got the high one, 80mA - 400A

author: PeterG
author_rank: Frequent Contributor
timestamp: August 27, 2011, 05:23:35 am
content: Read the manual before you buy one of these meters. I have seen clamp meters that will only measure High currents, some 5A or more, with the clamp. These meters will measure mA with the supplied leads only.Regards

author: ejeffrey
author_rank: Super Contributor
timestamp: August 27, 2011, 08:19:51 am
content: Devices advertised as 'leakage clamp meters' can usually read down to milliamps. However, they are not the cheapest -- the name brand ones cost similar or a bit more than their high current brethren, while the el-cheapo manufacturers tend not to make them.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 27, 2011, 01:02:20 pm
content: Tektronix and Lecroy make current probes that can resolve down to 10mA or so. I'm pretty sure they're really expensive, though.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 27, 2011, 01:52:48 pm
content: Quote from: NiHaoMike on August 27, 2011, 01:02:20 pmThese are generally high bandwidth probes intended for use with oscilloscopes, so yeah: considerably more expensive than units intended for DC or line frequency.

author: lebeno
author_rank: Newbie
timestamp: August 28, 2011, 12:16:00 pm
content: Maybe these probes are suitable:eBay auction: #230660053748,eBay auction: #200643395617

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 28, 2011, 11:45:19 pm
content: Nothing no-name is suitable about measurements.

author: qno
author_rank: Frequent Contributor
timestamp: August 29, 2011, 04:16:33 pm
content: DC current clamp meters are based on Hall effect sensors.For low currents you need extensive permeability (metal or ceramics).Making high mu metal is very expensive and ceramics are sensitive to damage. it is very brittle.Shutting the clamp wit a bang can crack the ceramic and make the current clamp useless.A well known failure with the old Tektronix current clamps.You need also an amplifier that enables you the compensate for the offset of the hall effect sensor.The fields surrounding a conductor at 40 mA are in the range of the earth magnetic field.Changing position according the the earth magnetic field can ruin your measurement.This is why there is almost no current clamp that measures these low DC currents.It is far easier to measure the voltage drop of a resistor to determine DC currents in the mA range.A trick you can use is to make 10 windings in the current clamp. This makes the field 10 times higher and the current clamp 10 times more sensitive.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 30, 2011, 12:18:05 am
content: Quote from: qno on August 29, 2011, 04:16:33 pmTrue.. as idea it stands, but its not easy to actually do it.https://www.eevblog.com/forum/index.php?topic=660.msg7847#msg7847

author: nukie
author_rank: Frequent Contributor
timestamp: September 09, 2011, 04:45:58 pm
content: 1mA no problem. German to the rescue!!Metraclip 41 will do just fine.http://www.gossenmetrawatt.com/english/nettable/clampmeters-overview.htmGMC-I CP 61 is the one you want with 12mm jaw for small diameter wire.http://www.alpha-electronics.com/LoadPDF.aspx?ImageID=5037&ProductImageID=5041

author: JuKu
author_rank: Frequent Contributor
timestamp: September 09, 2011, 06:52:44 pm
content: Klein tools CL1000 and CL2000 have a 2000uA range.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 09, 2011, 07:04:30 pm
content: No Idea of cost buthttp://www.elektor.com/news/novel-current-probe-measures-currents-in-pcb.1941158.lynkx?utm_source=UK&utm_medium=email&utm_campaign=newsseem to fit the bill.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 09, 2011, 07:44:31 pm
content: Quote from: FreeThinker on September 09, 2011, 07:04:30 pmGBP495http://www.tti-test.com/go/iprober/index.htmhttp://www.electronicsweekly.com/Articles/2011/09/01/51780/aim-tti-works-with-cambridge-university-on-micro-fluxgate-current-probe.htm

author: FreeThinker
author_rank: Frequent Contributor
timestamp: September 09, 2011, 07:54:48 pm
content: Quote from: mikeselectricstuff on September 09, 2011, 07:44:31 pmOuch!but if it's what you need........

author: Lawsen
author_rank: Frequent Contributor
timestamp: September 11, 2011, 10:24:39 pm
content: When measuring current in minute amounts, or milli or micro A, there is the problem with noise as mentioned in the above replies. The instrument is costly:http://www.gossenmetrawatt.com/english/produkte/metraclip64.htmThe technology exists as clamp on small current clamp on probes as mentioned in the above replies. I do not have experience with this instrument to describe further details.