Micsig CP1003/CP503 100MHz/50MHz Current Probe - Page 1
Forum section: electronics / testgear

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 12:03:07 am
content: Anyone interested in the Micsig CP503B 50MHz current probe that's coming out?https://www.micsig.com/CP1003/I'm thinking of stocking it. Can get a reasonable price for 50 units.The B version has standard BNC for use on any scope, other version is Micsig custom interface.Could sell the 50MHz version for under USD$500

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 12:10:46 am
content: QuoteAre you sure ?EDIT:Talking about prices

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 12:49:18 am
content: Quote from: Martin72 on November 19, 2022, 12:10:46 amYep. They have already given me a 50qty price.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 01:07:15 am
content: WTF...Do you ship to germany ??If yes you can bet on it I want one...Then testing it and if it´s good, maybe order 2 or more for the company I´m working for.

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 01:59:26 am
content: Quote from: Martin72 on November 19, 2022, 01:07:15 amI can ship to Germany.They said a sample will be available at the end of the month.I don't have a comparatively high bandwidth current probe to compare to though, but can of course check against a series resistor.

author: Psi
author_rank: Super Contributor
timestamp: November 19, 2022, 02:03:22 am
content: Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 02:03:42 am
content: I would test it simple way,First with the bodnar pulser and (internal)50ohms(doing bode plot), then taking to work and compare it on several measures with the still unbeatable A6302 probe from Tek...QuotePls pm me when you can do it.

author: tautech
author_rank: Super Contributor
timestamp: November 19, 2022, 02:17:33 am
content: Quote from: Psi on November 19, 2022, 02:03:22 amDo you need one ?I think we have some 200A probes left.

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 02:19:27 am
content: Quote from: Martin72 on November 19, 2022, 02:03:42 amI could take a risk and order 50 units now sight unseen. But otherwise it's end of month to get one, then testing time, then order, then however many weeks/months to get them.What to do...

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 02:20:32 am
content: Quote from: Psi on November 19, 2022, 02:03:22 amI guess that's possible. Never tried it myself.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 02:30:51 am
content: Quote from: Psi on November 19, 2022, 02:03:22 amWe also got the A6303 Probe from tek, which can measure up to 100A.To use it (or the 50Mhz A6302) for higher currents there´s a simple trick avaible.A "current divider"...Say 1:10, take 10 wires absoutely with the same length (crimped together on both sides)as a kind of link in the circuit current flowing.Then hook the probe in one of the 10 wires and measure the current, multiply it with 10...It´s the opposite of turning several wires around the core (this you do when you got less current flow)Tosimulatemore current as you got you turn multiple wires to the core.Tomeasuremore current than your probe can, you use a divider.

author: tautech
author_rank: Super Contributor
timestamp: November 19, 2022, 02:32:32 am
content: Quote from: EEVblog on November 19, 2022, 02:20:32 amIt's an old as the hills trick and even mentioned in old Tek documentation and one reason why we won't stock current probes with tiny cable holes so to get multiple wraps into them.

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 02:55:17 am
content: Quote from: tautech on November 19, 2022, 02:32:32 amNo, this is the opposite. Not multiple turns to turn a large current proce into a smaller current probe, but a single thicker wire paralleled with a thinner wire that goes through the current probe to turn a small current probe into a bigger current probe. Probaby easier to use say 10 wires of the same diameter and then only clamp one of them, bingo 1:10 probe.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 02:59:53 am
content: See my last post here.

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2022, 05:39:08 pm
content: Quote from: EEVblog on November 19, 2022, 01:59:26 amI have to admit this is a very interesting current probe.Realistically: how much is MicSig selling these for through their own Aliexpress / Amazon / Ebay store? And how about dealers in Europe like Batronix? My guess is that shipping costs and VAT are going to make the market for overseas orders quite small.Also, I would really like to see some actual tests where it comes to noise performance and looking at small currents before I would consider getting one myself.

author: Hydron
author_rank: Super Contributor
timestamp: November 19, 2022, 06:09:14 pm
content: <$500 is a pretty ground-breaking price if these are the same type of probe as Tek/Hikoi, i.e. thin-film hall sensor with nulling coil/amplifier. Still pricey but we certainly would have bought a couple in a place I worked where the $4k or more to get a tek probe+amp put off the bean-counters (we muddled through using an iProber). I'd even consider $500 for a hobby purchase - these type of probes (where you're not worrying so much about nulling the earth's field, or <5MHz BW limiting their use) are pretty great to have available.Dave, a quick and dirty way of measuring them would be to break out a sig-gen output via a loop section big enough to clamp around, then terminate it with 50R and derive the reference current from the voltage across the termination (is this what you meant by series resistor?).There are some high-BW CTs you can pick up second hand as well for comparison, e.g. some of the Tek CT-x range, or Pearson units (I've got a couple of these:https://pearsonelectronics.com/pdf/2877.pdf) but they normally go for good money. It's not necessarily trivial to get a good measurement result once you get to those frequencies though, either to characterise the probe or for in-circuit use, so I'd say that any sizable premium for the 100MHz version vs the 50MHz one wouldn't be worth it in most cases.

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2022, 06:18:40 pm
content: A really good test is to use a square wave current (1A / 10A) with steep edges so you can see whether the changeover between HAL and inductive sensing is working correctly.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 06:32:31 pm
content: QuoteIt got degaussing function so I guess it follows this principle.Last year I got a tek clone from instrance, not bad, better than all probes you can buy without degaussing, but it got overshoots and the inside building quality was bad.So hopes are high micsig will do it better, the CP2100 series from micsic are having a superb building quality outside and inside...

author: electr_peter
author_rank: Unknown
timestamp: November 19, 2022, 10:20:51 pm
content: OnSaelig site, CP503/CP1003 is ~500-700 USD, CP503B/CP1003B is double(!) at ~1000-1200 USD. Price difference makes no sense to me, because B version just has different form factor with same specs.CP503B at ~$500 is interesting, though.

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 10:31:20 pm
content: Quote from: electr_peter on November 19, 2022, 10:20:51 pmSounds like I'm going to own the market then

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 10:34:56 pm
content: Quote from: Hydron on November 19, 2022, 06:09:14 pmYes. Function gen direct outputas are limited in output current though, so I'd have to find another solution. But yes the idea is series resistor that can be scoped for comparison. If not ground referenced then I can use my HVP70 70MHz diff probe or a floating scope.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 10:35:27 pm
content: Quote from: electr_peter on November 19, 2022, 10:20:51 pmLook again....One fits only in micsig scopes, the other(B) is universal for all scopes and got dedicated circuits for it.Dave:Which version will you get ?

author: EEVblog
author_rank: Unknown
timestamp: November 19, 2022, 10:37:30 pm
content: Quote from: Martin72 on November 19, 2022, 10:35:27 pmThe B version for all scope of course. Practically zero market for a Micsig interface unit.

author: Martin72
author_rank: Super Contributor
timestamp: November 19, 2022, 10:46:09 pm
content: Hm...QuoteTherefore it makes sense when this version is cheaper...or not, I´m a little bit confused.https://www.saelig.com/micsig/cp503b.htmThey want double the price you offer, but same price (499) for the version which fits only to micsig scopes.https://www.saelig.com/micsig/cp503.htm

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2022, 11:04:56 pm
content: Quote from: EEVblog on November 19, 2022, 10:34:56 pmI have a DC load that is switching (low inductance planar) resistors through MOSFETs to achieve various resistance values. It can do seriously steep current changes in 'PSU torture' mode. It is only limited by wire inductance.

author: tomud
author_rank: Regular Contributor
timestamp: November 19, 2022, 11:58:40 pm
content: Quote from: EEVblog on November 19, 2022, 01:59:26 amHmm, attractive price, I assume that shipping to Poland would also be possible. Although I need to check what price will come out with all taxes and customs fees.

author: electr_peter
author_rank: Unknown
timestamp: November 20, 2022, 11:06:42 am
content: Quote from: Martin72 on November 19, 2022, 10:35:27 pmBoth could be universal if used with proper adapter. Adapter is magnetic and has USB C input for power, but makes the thing a bit long (risk of damaging BNC). I presume that adapter will be available and work the same as withDP750.However, adapter PA05 is 5V 1A, but required power is 5V 3A. No official adapter is available at this point.

author: Martin72
author_rank: Super Contributor
timestamp: November 20, 2022, 11:18:47 am
content: Hi,Yes but there is no adaptor included and no hint that there will be a adaptor separately offered.Additional, when I were micsig I would offer only one model instead two, when the one could be used with adaptor for all scopes.Why having two model lines...BTW,Datasheet :https://www.saelig.com/supplier/micsig/hf-current-probe-catalog-221018-saelig.pdf

author: Martin72
author_rank: Super Contributor
timestamp: November 20, 2022, 11:57:25 am
content: This is the CP6030 from Siglent(Hioki), nearly same looking but more than fourtimes expensive (2070€ without VAT).Same claimed accuracy of 1%, but, and this may be the pricedifference, +/-1mA in 5A range, +/-10mA in 30A range.(micsig: 10mA/50mA)

author: Martin72
author_rank: Super Contributor
timestamp: November 21, 2022, 06:44:42 pm
content: After request, batronix will offer the probes also and because they´re in germany, I´m probably out...

author: Martin72
author_rank: Super Contributor
timestamp: November 25, 2022, 10:55:35 pm
content: Hi,To get an idea why the micsigs are highly interesting, four other currentprobes (pic below, don´t get it why the pic in post function still won´t work).Testec and the "cheap" R&S doesn´t have degaussing function and worse basic accuracy, lower bandwith.Rigol and the second R&S do have this like the micsig, also the bandwith and the basic accuracy when you look only on the percent (1%).Rigol needs an additionally supply.But the main thing is, look at their prices....Hope, Dave could do a test soon.Martin

author: EEVblog
author_rank: Unknown
timestamp: November 26, 2022, 01:54:10 am
content: Quote from: Martin72 on November 25, 2022, 10:55:35 pmThat's the kicker. Still I bet a lot of people will say they are expensive.

author: Martin72
author_rank: Super Contributor
timestamp: November 27, 2022, 12:12:23 am
content: Yeah because they don´t know what´s behind I guess.First the bandwith, 50Mhz or 100Mhz are "outstanding", then the measure principle itself.For decades you could get this only from tektronix, later from hioki.Prices between 3000...5000.The first "cheap" one I knew was from Instrance, I´ve bought it 2yrs ago.User TopQuark got another one from another "brand".Problem of the instrance was noise ( not too bad but remarkable) and overshoots.Now the attempt of micsig...Knowing their CP2100 probes I have faith in it that they won´t perform too badly.Let´s see if micsig will do it better than instrance.

author: Martin72
author_rank: Super Contributor
timestamp: December 18, 2022, 10:15:17 pm
content: Anything new here?

author: jonpaul
author_rank: Super Contributor
timestamp: December 19, 2022, 01:51:36 am
content: Bonsoir just saw this interesting thread.Have acquired, used and tested current probes since 1970s, as SMPS, electronic ballast and consulting.Used them a lot in debugging,'uch more information than just voltage probes.Our collection is Tektronix, Yokogawa, and Pearson (passive CT)ranges up to 100A DC and 1000A AC, with Tektronix matching amplifiers.Usual test with Tektronix PG506 or PG508 into 50 Ohms term to make 1x or 10x loop.Issues to check3 db BW, (not 6 db!) rise time,pulse abberation ( overshoot)DC offset adjustment,degauss effectiveness, DC drift with warmup and temperatureCMRR eg with 500V H bridge wire the fast rise on the probed wire will couple into the currency probeEasy test probe wire with 0 current, drive wire from HV pulse gen or H bridge,find CMRR of probe.Cables are reasonable thickness and flexibility on Tek except old P6042.Any probe requiring power may be specific to an input scheme that's propriétaire.Scope probe external power sockets are not standardized, eg identical Lemo 4 pin on Tektronix and Yokogawa but 12vs 15 V and different pinoutSo, beware the fragile cores, dropping the probe even 100mm on hard surface can cause hairline cracks.Would reccomend the vendor send Dave a sample for test and eval BEFORE any qty order.If one is willing, ship a probe to me ( have USA drop) and I can test and write an evaluation.Just the ramblings of an old retired EEJon

author: EEVblog
author_rank: Unknown
timestamp: December 22, 2022, 06:59:40 am
content: Quote from: Martin72 on December 18, 2022, 10:15:17 pmHaven't heard anything.

author: Martin72
author_rank: Super Contributor
timestamp: December 23, 2022, 11:21:42 pm
content: Meilhaus electronics have listed the probes:https://www.meilhaus.de/en/micsig-cp-hf.htm1178€ (incl VAT) for the CP503B...And nearly the half for the Non-B version....And eleshop also:https://eleshop.de/micsig-cp503b-current-probe.htmlSame as Meilhaus, double-price for the "universal" version....It´s confusing...Edit: Batronix had told me in November the prices for the probes, I'm afraid they also refer to the non B versions....When Dave could offer the B-Version for 499, I´ll walk and swim to Australia for getting one at this price..

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2023, 10:43:01 pm
content: More and more are listing the new probes, partly on stock.But all got one thing in common, the "universal version" costs double than the UPI version...For appx 600€ (incl.VAT) I would buy one just for testing, but not for appx 1200...

author: jonpaul
author_rank: Super Contributor
timestamp: January 25, 2023, 11:52:53 am
content: For 600..1200 EU you can get a very fine TEK vintage probe with amp.Check epay for Tektronix current probesJon

author: JPortici
author_rank: Super Contributor
timestamp: January 25, 2023, 12:20:03 pm
content: Quote from: EEVblog on November 26, 2022, 01:54:10 ampeople that are used to cheap crap you can "hack"?

author: Fred_47
author_rank: Contributor
timestamp: January 25, 2023, 03:04:43 pm
content: Quote from: EEVblog on November 19, 2022, 02:55:17 amThere will be a small additional voltage drop in the wire thru the core because of the probe, that doesn't occur in the bypass conductors. Whether it is large enough to matter is a subject for experimentation.

author: Martin72
author_rank: Super Contributor
timestamp: January 25, 2023, 06:13:03 pm
content: Quote from: jonpaul on January 25, 2023, 11:52:53 amYes and I also have one because is still unbeaten in terms of performance, apart from the very expensive current probes from hioki, which run under different names.(which are equal, not "better")(R&S, Lecroy, Rigol and Siglent...no kidding).Siglent probeRigol probeR&S probeLecroy probeAnd that's the problem, the old Tek system is great but very space consuming, the nice narrow probes from Siglent and co. way too expensive.And so I've been waiting for a good and yet inexpensive probe from China....To date, all I had up to 600 € were nothing.From this point of view, the 1200€ would be a bargain, the Micsig would bring a very similar performance.But you do not know currently and even if it would be "only" 1200, I do not want to play a test rabbit this time.Plus I really do not understand why the universal "B" variant costs twice as much as the one for micsig scopes only.

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 25, 2023, 06:41:31 pm
content: One problem with clamp probes is that CMRR is either not specified or is very bad. Historically CMRR was not a very demanded spec in current probes so the trend of not asking for it has continued.So for high side/floating current measurements, there is going to be a nice distortion.

author: EEVblog
author_rank: Unknown
timestamp: January 26, 2023, 12:37:00 am
content: Quote from: Martin72 on January 25, 2023, 06:13:03 pmIt shouldn't from what I've been quoted wholesale pricing for the B varient.

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2023, 12:51:47 am
content: Rebonjour, cher PartialDischarge ..." clamp probes ...CMRR not specified or is very bad.for high side/floating current measurements, there is going to be a nice distortion"Well there is not a "high sided distortion" but a predictable CM noise coupling proportional to Dv/Dt of the circuit probed and the stray C probed wire to probe body.Thus CM current = Icm = C dV/DtIn 55 yrs we never had a problem with a current probe CMRR.No spec as the coupling depends on conductor size and position in probe jaw aperture.Cp-s is perhaps a few pF.But any CMRR issue is easy to solve.1. Place probe at rtn/low side of circuit not at high side, eg BJT NPN emitter or FET drain.Thus the CM voltage is minimum, near ground.2. Make a small copper shield around the conductor, with a slit to avoid shorted turn/Wrap the shield tightly around the conductor. No shorted turn!Ground the shield: Voila a Faraday shield.Jon

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2023, 02:36:29 am
content: Rebonjour a tous:Your questions re TEK CT and CMRR sparked my curiosity.I unearthed my collection of CT and DC hall TEK probes, circa 1980s..1990 at ham fleas in SV, epay, since 2000 and (sadly) ham friends silent keys.For SMPS, arc lamp ballast, pulsed power, R&D, consulting and magnetics design.With HP LCR meter 4332A, with a short insulated wire stub, 3 pF range, zero out wire stub, 20..50 mmCap Probe return/body to wire.P6022 0.75pF (AC passive, LF 3 db 8.5 kHz)p6021 0.85 pF (AC passive, LF 3 db 450 Hz)P6302 1.0 pF (active hall DC-50 MHz)P6303 0.58 pF (active hall 100A huge gun )Conclusion: CMRR is not an issue, external Faraday shield unneeded.stray C of test setup and DUT will swamp the under 1 pF C current wire ><probe return.TEK has grounded the metal shell or shield of the probe CT and Hall device so a built in Faraday shield.Your thoughts appreciated!Have an ABSOLUTELY FANTASTIC day,JonPS:Probe size relates to core area, thus sensitivity and LF /HF rolloff point.For very AC only we use TEK P6021 and much smaller TEK P6022PPS: Yokogawa current probes are also excellent but the probe power is a proprietary pinout, +/- 12 V on a 4 pin Lemo.

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 26, 2023, 08:26:08 am
content: Quote from: jonpaul on January 26, 2023, 12:51:47 amNever had problems because as you mention you did avoid it by measuring low side. Also nowadays stacked or multilevel topologies are quite common which was not the case 20 or more years ago.Quote from: jonpaulWrong conclusion.The capacitances you mention are only relevant to calculate how much current goes into the current probe from your circuit (loading purposes) but says nothing about how the measure will be affected.Of the probes listed I only saw the RS having CMRR data, and it is not bad, but extremely bad, only quoted to 20KHz, I can imagine at 1MHz is it like 20dB.

author: thaamike
author_rank: Newbie
timestamp: February 12, 2023, 01:01:27 pm
content: Any luck getting these probe for the nice price ?

author: EEVblog
author_rank: Unknown
timestamp: February 12, 2023, 10:07:57 pm
content: Quote from: thaamike on February 12, 2023, 01:01:27 pmI've just asked again for the sample.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2023, 11:15:51 am
content: Quote from: EEVblog on February 12, 2023, 10:07:57 pmThey got back to me. The R&D team are all working on the isolated probe and have no time to finish the current probeso there will be delays.Sounds like they think the isolated fibre optic probe will overtake the traditional high voltage probe, they want to know if I'm interested in getting one.

author: nimish
author_rank: Regular Contributor
timestamp: February 19, 2023, 01:42:51 am
content: Quote from: EEVblog on February 13, 2023, 11:15:51 amIf you can sell it for less than $10000 yeah. IsoVue probes are not cheap to replace...

author: mawyatt
author_rank: Super Contributor
timestamp: February 19, 2023, 02:04:09 am
content: Quote from: EEVblog on February 13, 2023, 11:15:51 amThis optical probe probably has much more potential $ ahead, so that's where the emphasis goes!!Get one if you can, that would be interesting to see what they've done. Wonder if they've found a way to pump enough optical power back up the fiber to power the head?Best,

author: mk_
author_rank: Regular Contributor
timestamp: February 19, 2023, 06:34:25 am
content: Quote from: mawyatt on February 19, 2023, 02:04:09 amWe probed a shunt riding on a 25kHz 700V Output (square, not sinus) with an earlyhttps://saker-mv.com/fiber-optic-isolated-voltage-probe-xfvp-l/. This worked fine so - there are cheaper and also working solutions which are not soooo expensive as those from Textronix.btw: somewere in the X-Chapters a detailed description for this optical probes from Tek can be found.

author: nimish
author_rank: Regular Contributor
timestamp: February 19, 2023, 07:36:01 pm
content: Quote from: mk_ on February 19, 2023, 06:34:25 amIt's a little ridiculous honestly. Makes one want to try to DIY a probe usinghttps://docs.broadcom.com/doc/AFBR-POCxxxL-DSor something. I'd rather spend $3000 than $7500+ to get isolated HV gan/sic measurements

author: Alphaprot
author_rank: Newbie
timestamp: April 11, 2023, 08:52:57 pm
content: I am still wondering how MicSig is going to justify the almost 2x price difference between the BNC and the UPI version which at least to the datasheet/catalog page and the CP1003/CP503 manual is indistinguishable performancewise. This makes no real sense to me other than forcing people onto your scope platform.

author: Martin72
author_rank: Super Contributor
timestamp: April 11, 2023, 09:25:34 pm
content: Or let me think about what´s in the box...Batronix still doesn´t offer them.

author: EEVblog
author_rank: Unknown
timestamp: April 11, 2023, 11:38:42 pm
content: Quote from: mawyatt on February 19, 2023, 02:04:09 amThey contacted me again recently, one is apparently on the way.

author: Bran Zhu
author_rank: Newbie
timestamp: April 25, 2023, 08:56:34 am
content: I just received CP253B today, the 25MHz version of this series. Micsig sold it at RMB3900(USD560) with tax in china. This is much cheaper then the 50MHz version, CP503B is listed at RMB12900(USD 1865).Maybe you can also consider this model.

author: Durong
author_rank: Newbie
timestamp: April 26, 2023, 06:30:59 am
content: Are you the person who posted the comparison with the Tektronix probe under their review section?The 50M version cp503b in Australia is around 5000 CNY after tax, half the price of their direct sale on Taobao.

author: gossamer
author_rank: Contributor
timestamp: April 29, 2023, 09:36:53 am
content: I wonder if cp503 would work with this upi to bnc adapter. Or is there something else significantly different between 503 and 503b ?

author: Martin72
author_rank: Super Contributor
timestamp: April 29, 2023, 10:42:17 pm
content: Short review:

author: Someone
author_rank: Super Contributor
timestamp: April 30, 2023, 12:00:55 am
content: Quote from: Martin72 on April 29, 2023, 10:42:17 pmMuch more than "short" ! the video has a very nice mixture of examples and discussing those back to the specifications. Noise performance is impressive for such low cost.

author: Martin72
author_rank: Super Contributor
timestamp: May 01, 2023, 09:48:03 pm
content: QuoteYepp...QuoteUnfortunately batronix still didn´t have the probes on their site listed - Otherwise I would ask them for a sample to test, like I did in february(Rigol DHO4024).I would like to compare the micsig with my tek probe(A6302/AM502A), I like the tek much but it needs sooo much space on the desk....

author: dirtcooker
author_rank: Regular Contributor
timestamp: May 15, 2023, 08:09:53 pm
content: Quote from: gossamer on April 29, 2023, 09:36:53 amThe spec sheet says it needs 12v. Perhaps a modified upi adapter would work. Does anyone have one of these to test?Also, the B versions require 5v 3A, so these probes are rather power hungry.I probed voltages on the upi adapter from my RCP500 and found supply voltages across the top row of pins.

author: dirtcooker
author_rank: Regular Contributor
timestamp: May 15, 2023, 08:21:07 pm
content: I recently bought a Micsig RCP500. This is a 500A rogowski ac current probe good to 300 khz, perfect for measuring phase currents on inverters, heat pumps and motor drives, and is portable and more convenient to use than my Tek probes. It pulls only 8 ma from a 5v USB jack so can be used with a battery pack. I did a couple tests on it which I will summarize here. The first using a deskew fixture, RCP500 is the blue trace, tek A6302 green, response to 150 ma pulse, both channels adjusted to 500ma per div. Note there are high levels of noise in the scope traces as I am in the city near radio transmitters.The second test is measuring drain current in a double-pulse test setup using two FGH60N60 IGBT's in a half bridge, with a 150 uH air core coil from drain to source of top IGBT. A Siglent SDG2042 with outputs summed controls the pulse train. 10 Hz rep rate is well below the RCP500's 15 hz -3 db roll off but even so there is no noticeable droop. It has about 2 us delay, and is not fast enough for estimating IGBT switching losses, but is reliable for measuring locked rotor amps without worrying about probe saturation.I just bought a second one on sale for $100https://www.sainsmart.com/products/micsig-rcp500-rogowski-ac-current-probe-300khz-with-standard-bnc-interface

author: DaneLaw
author_rank: Frequent Contributor
timestamp: May 17, 2023, 02:53:36 am
content: Quote from: dirtcooker on May 15, 2023, 08:09:53 pmI don't know what ampere it uses in practice, as I havent tested it, but Micsig's official power specs, some of those should be taken with a pinch of salt, at least in the past.I recall somebody looking for a PSU for their Micsig-tablet-scope's, and was hard-set on matching Micsigs official PSU 12v/5.417A (65watt)https://tinyurl.com/6zkhze47though these scopes are not anywhere close to using that, it's under 50% of that, around 25W "charging" and around 30W "in use & charging" and the org Micsig PSU was somewhat noisy.https://tinyurl.com/3v5v6a47I don't use the incl PSU with my Micsig scope, just use power banks with PD 12v support, and with a TypeC to DC barrel decoy-adapter.But I do recall that Micsig indicating the "B-variant" for their Micsig-scopes without Micsig's new proprietary prope-interface and gave the impression it could be run from the scopes USB, and the USB-port in all these Micsig-scopes are not able to deliver anywhere around 5V-3A, not even half when I run the secondary display from it and had to dial down the brightness..https://tinyurl.com/24hn9rcw

author: LTXAPAS
author_rank: Newbie
timestamp: September 29, 2023, 08:07:25 am
content: Quote from: dirtcooker on May 15, 2023, 08:09:53 pmHas anybody tested the CP503 with the accessory in a normal oscilloscope? (using the right voltage)...

author: gossamer
author_rank: Contributor
timestamp: October 02, 2023, 05:23:13 pm
content: Seems like UPI ones are now discontinued according to the Micsig website.. whats that about?CP1003 / CP503 (Discontinued)B versions are still on the market

author: DaneLaw
author_rank: Frequent Contributor
timestamp: October 02, 2023, 08:40:09 pm
content: Quote from: gossamer on October 02, 2023, 05:23:13 pmMicsig seems to end' its "Universal Probe Interface" (UPI)I reckon they had hoped that other vendors would jump on board on their UPI standard, and later realized it would be a task to operate with two somewhat proprietary probe interfaces for a relatively small international vendor like Micsig.As they had both their "UPI probe interface" and their "OPI probe interface"The only scope models, I so far have seen Micsig OPI-sockets on - are their ETO-model & their coming MDO-line.https://www.eevblog.com/forum/testgear/new-micsig-scope-with-knobs-(again)/msg4854149/#msg4854149-UPI [Universal Probe interface]Mic-OPI [SigOfit..)

author: Martin72
author_rank: Super Contributor
timestamp: October 02, 2023, 09:00:55 pm
content: Quote from: gossamer on October 02, 2023, 05:23:13 pmAnd one shop offers the Non-B probe for 41% off...https://evision-webshop.de/micsig/cp503-strommesssonde344€ incl. VAT/486€ for the CP1003....

author: amar87
author_rank: Regular Contributor
timestamp: January 04, 2024, 05:13:31 pm
content: I bought a CP1003B. In case someone is interested i could do some experiments and post the results. After all the things i learned from this forum is the least i can do.

author: Martin72
author_rank: Super Contributor
timestamp: January 04, 2024, 05:19:12 pm
content: Do it please...Noise, bandwith, accuracy....

author: amar87
author_rank: Regular Contributor
timestamp: January 04, 2024, 06:07:57 pm
content: I am not sure how to measure the noise from it. I could plug it in the scope and change the ranges and see the peak to peak and the RMS values. I would maybe need some help ony hwo to conduct the experiements, i guess out of all of this i could learn a thing or two as well.For DC a could compare it with a 6 1/2 multimeter to determine the accuracy.For AC i have acces to a calibrated AC current source i have to see when i can use it. But it can do 40...60 Hz or someting like that.To determine the bandwith i have a RIGOL 100 Mhz DG4102 I guess i could i could short the output into 50R or something and see where the rolloff occurs but i guess with this the onyl thing i could find out is if the the bandwidth would be under 100 Mhz.Would also approciate some pointers as i never really qualified a current probe before. Some 'pre-experiment feedback' would be appreciated.

author: amar87
author_rank: Regular Contributor
timestamp: January 04, 2024, 07:14:16 pm
content: So i am not sure if what i did is super correct but here it goes :Test setup for noise measurement:- Siglent scope SDS2104X- 200 Mhz Bandwidth - this made sense to me since the current probe is 100 Mhz- Pressed the 'ZERO' button on the probe- Enabled the measurement function on the scope to show RMS, Mean, Peak to Peak and the Stdev measurement which i think but not 100% sure is the RMS without the DC component and the RMS contanints the DC component- no cable through the loop.This is what i can measure with the probe on the 6A range:This is what i can measure on the 30A range:Test Setup for Accuracy 6 A range :- same as above + the following:- DC electronic load- Fluke 8846A Multimeter (not calibrated)- DC power supplyTest Setup for Accuracy 30 A range :same as 6A rangeI am not sure how to interpret the±10mA（6A)after the ±1%±10mA（6A) (spec from datasheet) maybe the experts can help here. I guess if i would take out the 10 mA somehow from the readings the probe could be in spec

author: Martin72
author_rank: Super Contributor
timestamp: January 04, 2024, 08:24:21 pm
content: Hi,Here are links to the probes I´ve tested (and other users in the thread):https://www.eevblog.com/forum/testgear/tek-clone-instrance-icp-5025-current-probe/msg3366960/#msg3366960In this thread I´ve tested the bandwith of a currentprobe via bodeplot:https://www.eevblog.com/forum/testgear/micsig-current-probe-cp2100b-tests-and-comparing/msg3072460/#msg3072460May I ask what you´ve paid for the micsig probe?

author: amar87
author_rank: Regular Contributor
timestamp: January 04, 2024, 09:06:07 pm
content: i will conntinue tomorow after reading your posts, i bought the probe from Meilhaus electronic last year probably the price is the same now i waited for it a long time and it also came with a china USB- 230V adapter, and you can't power it from the scope because it needs some more juice than the scope can provide, it also seems that it doesn't want to work with other phone chargers i had arround .

author: Martin72
author_rank: Super Contributor
timestamp: January 04, 2024, 09:26:26 pm
content: Hi,QuoteIf you compare this with a multimeter, I would also measure the output of the current clamp with a multimeter.There are BNC to banana plug adapters.Apart from that, I'm no longer surprised that the current clamp is so "off" at very low mA values after I've seen the specs.There the measuring range is specified from 20mA or 50mA (6A/30A).A bit sobering as far as the 6A range is concerned.Seen earlier, Batronix now also has them on offer, both variants in stock.https://www.batronix.com/versand/messtechnik/tastkoepfe/Micsig-CP503B.html

author: amar87
author_rank: Regular Contributor
timestamp: January 04, 2024, 10:34:56 pm
content: Yes i expected it to be off at currents lower than they give in the datasheet, you are absolutely right. i just put those measurements in there because i wanted to see how bad it is or to better put it if it could be used. But what i observed is that the error (below 20mA in the 6A range and below 50 mA in the 30A range) is mainly caused by the offset that it has after zeroing. What i also observed that this offset has a tendency to drift after zeroing. maybe some interesting experiments would be observe when it stops drifitng. Strictly speculating with the info i have at the moment this could be the the reason why they give the +/- 10Ma after the percentage.I can also plug it in the multimeter witha BNC Banana adapter, but then how to compare it ? The DC load i used (Rigol DL3021A) needs to be stable. (which i have no idea how stable it is ), i could take a reading DC load on X mA in the shunt of the multimeter, then same with current probe plugged in the multimeter on voltage? Then we don't know how accurate the multimeter is on voltage vs on current. Then the sampling rate and bandwidth from the multimeter is lower than the scope.......... This makes me go crazy....How i did it before i am actually showing the error from the scope + the error from the probe actually(which is also not very scientific ).... this is not easy to do...What confuses me here is the spec of +/1%+/-10mA(6A Range) and it measures above 20mA whatever is under that you can't trust. Let's assume my fluke is perfect. i read on the fluke 22.9 mA on the scope 25 mA. Is the probe in spec or not ?Also the reason for not testing over 6 A is that i have no power supply that provides more than 6A.

author: Martin72
author_rank: Super Contributor
timestamp: January 04, 2024, 10:44:49 pm
content: QuoteYou can turn windings over the core of the clamp.Example:Turn a wire (Measure lead) 5 times around the core, feed in 1A, the currentclamp will measure 5A...Like I did in the pic below.QuoteFor me it reads as +/-1%, but at least +/-10mA.

author: _Wim_
author_rank: Super Contributor
timestamp: January 05, 2024, 07:03:15 am
content: Quote from: Martin72 on January 04, 2024, 10:44:49 pmI would expect this to be the sum of both: so +-1% of the measured value plus an additional +-10mA. This means when putting 6A through, you end up with +-70mA.

author: _Wim_
author_rank: Super Contributor
timestamp: January 05, 2024, 07:52:41 am
content: Quote from: amar87 on January 04, 2024, 10:34:56 pmThis is typical for a probe like this. My fluke I50 also drifts after zeroing. I think you are correct that the +-10mA comes at least partly from this drift, and hence the accuracy is specified as the sum of the drift and the measurement error.Quote from: amar87 on January 04, 2024, 10:34:56 pmI am not completely sure why you want to do this, but if it is to rule out errors from the scope, I would just check the scope DC voltage accuracy vs your multimeter. But as you are using a 10bit scope, I do not expect here anything significant vs the 1% error you are trying to verify. For me it looks like the probe is meeting is spec for DC accuracy everywhere apart from the 2A measurement on the 6A range where it just barely exceeds it, but this could be due to tolerances in the test setup. Noise is also quite ok from the looks of it.For the AC noise, can you put the bandwidth limit to 20MHz on your scope and report the ACrms and ACpp? This should according to the datasheet be below 1.4mArms when limited to 20MHz.

author: amar87
author_rank: Regular Contributor
timestamp: January 05, 2024, 10:50:39 am
content: The requested screenshots with 20 Mhz bandwidth:6A range :30A range 100 ms/div :I am not sure which figure to take looking at the STDEV measurement on the scope which i think is the RMS without DC component but not sure and playing with the timebase the noise can be lowerHaving 20 ms/div i get this :Then 20 ms/div and change aquisition to average i get this:So i don't know how to measure to verify the≤ 1.4 mA RMS (Bandwidth at 20 MHz, Range 30A, 10X)spec

author: amar87
author_rank: Regular Contributor
timestamp: January 05, 2024, 11:29:31 am
content: I tried doing some bode plot using the internal signal generator from the scope that goes up to 25 Mhz but i think i am doing something wrong and don't know what but i would have expected the bode plot to be flat. I am attaching a few pictures so don't laugh.....i wanted to see if the magnitude line is flat and does not change up to 25MhzHere is the test setup and the scope setup for the measurement:In Ch1(1 Meg ) i pluuged the output from the current probe in CH2(50 Ohm ) the input from the internal generator and the red wire is also looped through the probe as much as it fits.I have to try with more windings i thing that is why i am getting crap.

author: Martin72
author_rank: Super Contributor
timestamp: January 05, 2024, 06:42:25 pm
content: Assuming the generator really delivers a 3vpp level, you would have to measure approx. 21mA with just ONE winding (i.e. simply connect the clamp to the cable).Because 3vpp is 1.06Vrms.This voltage divided by the 50 ohms is 21mA.The output of the clamp delivers 500mV/A, i.e. 10.6mVrms at 21mA.That would be a factor of -40dB for one winding, you have several windings and approx. -67dB.

author: _Wim_
author_rank: Super Contributor
timestamp: January 06, 2024, 03:26:43 pm
content: Quote from: amar87 on January 05, 2024, 10:50:39 amI would just put the scope channel into AC-coupling to avoid DC offset errors. The standard deviation is not the correct measure. Subtracting the "mean" value from the "RMS" will be closer, but I am not sure is this is mathematically correct also.

author: amar87
author_rank: Regular Contributor
timestamp: January 06, 2024, 09:44:49 pm
content: For the bandwidth i have an 45W RF amplifier that can do 150kHz -250 Mhz , i need a high power terminator which i have to get my hands on i already asked arround to borow one , i will try to do it like this. I guess it could work if i remove the shielding from a coax and them solder a wire somehhow over the shielding so i can put the probe over the inner conductor + teflon would work.I can use my siglent scope on the FFT function (hope it has MAXHOLD) with the current probe plugged into it and then sweep the output of the RF Amp into a terminator and monitor the coax with the current probbe.The above procedure should give a nice line and rolloff so we could see the bandwith i guess. Please correct me if you see something wrong in what i described above.

author: Martin72
author_rank: Super Contributor
timestamp: January 06, 2024, 10:28:06 pm
content: Hi,QuoteHas it:https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg5213874/#msg5213874

author: Martin72
author_rank: Super Contributor
timestamp: January 06, 2024, 11:37:15 pm
content: Hi again,QuoteThis will also work, you may not even have to solder anything.I have done this before and am doing it again.At the moment the Bodeplot is running and the current clamp is the tektronix A6302/A501A combination.I have set a 1Vrms and the load is simply the input resistance of the scope, as previously discussed and as you have already done.The Bodeplot should have no problem with these low levels because the scope itself has no problem with them.I had tested up to 100Mhz and am currently running it up to 50Mhz and maximum number of points, which takes a while....Final then still with 20Mhz bandwidth limitation.Pictures will follow soon.

author: Martin72
author_rank: Super Contributor
timestamp: January 07, 2024, 12:24:15 am
content: Here are the results of the good old Tekprobe...It has a bandwidth of 40Mhz (-3dB), the pictures show the bodeplot once with and without faded-in phase, then again only this time with active bandwidth filter of 20Mhz (switched on at AM501), plus finer resolution of 2dB/div.That was the setup with external generator, "tomorrow" I will reproduce your first attempt 1:1 with the internal generator.

author: Martin72
author_rank: Super Contributor
timestamp: January 07, 2024, 04:02:05 pm
content: I have now also tried it with the internal AWG of our 2000X HD, without any problems.Once with your settings, i.e. 10pts per decade, once with 50.The finer you resolve the amplitude, the more "terrible" the transmission looks, but if the plot is between +/- 0.5dB, I think it's good.If you take a resolution of 6dB, you will of course have a dash.Well, what does that tell us now?That it works as you had previously thought, even without several windings through the core.So something must have gone wrong with your attempt, check again.Oh well:And the course of the transmission as shown in the data sheet of the CP1003B can safely be regarded as an idealized plot, it will not be the truth.Martin

author: Martin72
author_rank: Super Contributor
timestamp: January 07, 2024, 04:03:27 pm
content: Last pic.

author: cameronb
author_rank: Newbie
timestamp: January 07, 2024, 11:53:19 pm
content: I picked up the CP503 from SAELIG. It looks to require only a 5V/3A supply. Noise is not critical as it drives a buck converter and linear regulator.Here's what's insideGDE232E (Arm Cortex).TI54331 buck converter + AMS1117 provide a clean 3.3V rail for the analog end of things.OPA4171 probably related to range selection from the DAC on the GDE232EAs far as I can tell, there are no electrical connections to the 3.3V and -5V rails.I've confirmed all the digital bits are running directly off the 5V rail.It's probably as easy as passing a USB cable into the housing. I'll try it tonight and report back.

author: cameronb
author_rank: Newbie
timestamp: January 08, 2024, 06:41:20 am
content: There's definitely a second rail on an unknown-to-me pin. I did, however, get the device and relay up and running off the 3.3V rail. I'm probing out a schematic right now.I'll have more updates later this week.

author: amar87
author_rank: Regular Contributor
timestamp: January 08, 2024, 12:43:45 pm
content: I tried some more experiment:First would be with the internal AWG from the scope.Second with the signal generator where i manually swept up to 100 MHZ, recoded the measurements into a spredsheet, converted to DB and made an ugly bode plot.if i compare the bode plot from the scope and the one from the spredsheet they don't really look alike. And that dip at 30 Mhz i don't get why it is. Maybe the probe is actually like this ...

author: idolclub
author_rank: Regular Contributor
timestamp: January 08, 2024, 06:05:40 pm
content: Quote from: amar87 on January 04, 2024, 09:06:07 pmThe maximum power consumption of CP1003B is about 5V / 800mA, typical 400mA.CP1003B also can work with Apple or Samsung 5V / 2A charger.

author: amar87
author_rank: Regular Contributor
timestamp: January 08, 2024, 06:06:24 pm
content: Quote from: cameronb on January 07, 2024, 11:53:19 pmIf you have the time could you also try to do same experiment as Martin and me and report back the result?

author: Martin72
author_rank: Super Contributor
timestamp: January 08, 2024, 07:19:56 pm
content: Quote from: amar87 on January 08, 2024, 12:43:45 pmI can't see any difference between your setup and mine, should the current clamp really be that "bad"...But I can't believe that this is normal for a model costing over €1000.Perhaps the people at Meilhaus can check this on another Micisg.

author: _Wim_
author_rank: Super Contributor
timestamp: January 08, 2024, 08:21:40 pm
content: Quote from: amar87 on January 08, 2024, 12:43:45 pmI would first try to figure out why you get different results. First thing I would do is make a bode plot of the signal generator only (so feed the signal both to the 50ohm input AND the 1M input. This should give a flat response, if not, investigate further.I also would try a figure out why with the external the signal goes down when the frequency goes up, and it is inverse with the internal signal generator.If you repeat the plot multiple times (with for example the internal signal generator), do you get everytime the same result, or is the result more random in nature?

author: _Wim_
author_rank: Super Contributor
timestamp: January 08, 2024, 08:26:48 pm
content: One more question, are you sure the slider is fully closed (should be in the "lock" position to measure)

author: Martin72
author_rank: Super Contributor
timestamp: January 08, 2024, 08:38:57 pm
content: Woah, Eagle-Eye!It could be, no, it will be.

author: amar87
author_rank: Regular Contributor
timestamp: January 08, 2024, 08:58:17 pm
content: Yes, will try again with the clamp in the locked position, i also think i am doing something wrong. Will do some more measurements when i have time. I want to get to the bottom of this.I have been thinking also the following : maybe 1 Vrms /50R = 20mA and it is exactly on the edge.

author: Martin72
author_rank: Super Contributor
timestamp: January 08, 2024, 10:32:03 pm
content: Please do that, the Micsig is still of interest because it is simply very compact compared to a Tektronix combi.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 07:20:49 pm
content: Aparently when having too many pictures inline the forum doesn't display the message correctly for some reason second time i write this .....I tried to check my setup first:_Wim_ suggested to see first if the bode plotter is ok so here we go:- CH1 1 Meg- CH2 50R- Used the 'butchered' BNCWe notice a 0.6 dB increase at 25 Mhz compared to the rest of the frequency range.Next i replaced the 'butchered' cable with normal BNC RG58The response i a lot flatter.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 07:38:24 pm
content: I wanted to see what happens if the probe will just stay on the coax.... so don't ask whySomething weird happens now this is a scope problem but however maybe it give a clue on the issueRan the bode plotter 2 times first run gives this:Second run:I can't explain the 3 dB shift. This is related to what _Wim_ said in a previous post.But my conclusion so far is having the probe on the coax does not change the frequency response wanted to see just in case.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 07:47:20 pm
content: Sorry for writing so many messages but i put everything in one and it somehow wasn't displaying correctly so i had to delete it.....After all of the above ran the test again this time with the probe inserted trying to figure out the reponse from the probe up to 25 MHz.Probe is locked this time:Displays 20 mA = 1 Vrms / 50R :And it give this bode plot (i also placed markers ):So i have reached the limit to what i can test..... the thing is not flat or my scope measures crap, but i don't know if the 2 dB should be right.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 08:09:32 pm
content: There is a Whatspp number on the Micsig website. i wrote to them they also said it can be the slider. I gave them the forum link and invited them to comment as well, maybe they will do.

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 08:40:37 pm
content: Your pictures are always opened separately, which is a bit tiring when the post is gone and only the picture is visible.I think the small increase that can be seen in the "cable test" is negligible, so the graph from the currentprobe is "real".Micsig should really take a look at this, the currentprobe is too expensive for that.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 08:58:31 pm
content: Fo the sake of completeness i also did an 'ugly' bode plot manually:Generator set to 50R output impedance, probe sldier closed.The scope is set to 1 Meg input for CH1 where the output of the probe is, 50R CH2 where the generator goes.Gives this :Welll..... i gues if you would imagine that that part i circled in blue would be flat like the yellow line, it can be like in the datasheet...Yes would really be nice if micsig would say something about this.....

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 09:11:26 pm
content: how to place the pictures so they open inline (sorry for the forum-noobness)?

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 09:19:56 pm
content: Hi,I have recreated your test with the cable only, it's just like that, no need to worry.It depends on the cable and the internal generator does not necessarily have to be ultralinear.

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 09:22:46 pm
content: QuoteOne possibility is to use the default setting (end of post expendable thumbnail).

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 09:52:41 pm
content: Before i put the setup away i thought i would do some pulses through it and see what it does.they sayDelay ＜ 30ns（6A )i kind of get 2x this much. this delay should be the delay between the input current and the output voltage.CH1 is the probe output.CH2 is measuring the voltage from the signal generator.Using the Skew Measurement and the cursors i get 69 nS.Is that delay parameter from the datasheet something else or am i measuring something wrong?

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 10:12:26 pm
content: I made a mistake in the previous post i had that deskew delay set in one of the channels of the scope. the delay is 15 nS which is lower than 30 nS so well in spec...

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 10:15:56 pm
content: Ah, very good.Do you have access to a (very)fast risetime pulse ?

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 10:16:45 pm
content: what you see there in the rigol screenshot the 7 nS is the fastest i have......

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 10:27:57 pm
content: OK, not..I have just asked Batronix if they would lend me a CP1003B for testing.Then I could make additional measurements and check it´s frequency response.

author: _Wim_
author_rank: Super Contributor
timestamp: January 09, 2024, 10:46:54 pm
content: Quote from: amar87 on January 09, 2024, 07:38:24 pmI am not sure how the bode plotting function on the siglent works, but the voltage show on channel on does differ from run 1 to run 2. I would however expected this bode plot to be zero dB gain or -6dB in gain (due to the 50 ohm input), I do not understand where these positive gains are coming from as they is no amplifier in the cable. Could it be that the "reference" and the "test signal" are swapped? Normally I expect a bode plotting function to report the difference in gain between the reference input and the test input, and in the case of only a BNC cable between the two, this should not create any gain...

author: Martin72
author_rank: Super Contributor
timestamp: January 09, 2024, 10:51:40 pm
content: My previous "only cable test" I did several times, always with the same result.

author: amar87
author_rank: Regular Contributor
timestamp: January 09, 2024, 11:14:21 pm
content: i had the probe input on 2x on channel 1 that is where the 'gain' is comming from.... sorry for the confusion.... The scope leaves it like that if you change from current to voltage. I just did not bother to change it.

author: Martin72
author_rank: Super Contributor
timestamp: January 10, 2024, 02:37:02 pm
content: Quote from: Martin72 on January 09, 2024, 10:27:57 pmNot, but they suggested to "buy" it and return inbetween 30days.And that´s what I did, should arrive in the next days.

author: Martin72
author_rank: Super Contributor
timestamp: January 11, 2024, 06:06:23 pm
content: Batronix, fast as lightening, as ever...

author: amar87
author_rank: Regular Contributor
timestamp: January 11, 2024, 07:24:53 pm
content: Cool! Let's see how it tests.

author: amar87
author_rank: Regular Contributor
timestamp: January 11, 2024, 07:25:55 pm
content: did yours come with an EU style power adapter?

author: Martin72
author_rank: Super Contributor
timestamp: January 11, 2024, 07:59:11 pm
content: Hi,Yes, with this one:https://www.knivesandtools.de/de/pt/-qualcomm-qc-3-0-usb-adapter.htmQuoteI'm also very curious, but I'll wait until tomorrow because the package was very cold.

author: Martin72
author_rank: Super Contributor
timestamp: January 12, 2024, 06:27:08 pm
content: Well...Here are a few results, I would still like to measure the risetime and accuracy.The noise is good, the delay is very good, but the linearity leaves a lot to be desired.Fluctuations of +/- 0.5dB, as with the Tek Probe, are still acceptable to me, but this...I'll try a few more things at the weekend.As things stand now, I wouldn't want them.

author: Martin72
author_rank: Super Contributor
timestamp: January 13, 2024, 05:52:32 pm
content: Hi,Trying to make an adpater for the bodnar pulser....Of course, this will not work without losses, that was clear.But the Amazon BNC to screw terminals are totally unsuitable for this - if they are in between, there is nothing left at the end that you could call a square wave signal...Well, then another setup and this one is much better, the rise time is still under 1ns.(Pictures from both will follow, forgotten)Used this adapter with the Tekprobe.The current is very small and "high frequency", two challenges that the Tekprobe can handle, see pictures.Then the Micsig...Tomorrow I will have my generator produce square wave signals at different frequencies, the current will then also be higher.To be continued.

author: amar87
author_rank: Regular Contributor
timestamp: January 14, 2024, 05:46:16 pm
content: So i was not crazy........ it happens as well at your side.

author: Martin72
author_rank: Super Contributor
timestamp: January 14, 2024, 06:33:27 pm
content: My aim with the "loan" was to determine whether there is a defect or whether this is actually the behavior.I would have preferred yours to be defective.

author: amar87
author_rank: Regular Contributor
timestamp: January 14, 2024, 08:37:38 pm
content: i love it how you dremeled the deskew fixture........

author: Martin72
author_rank: Super Contributor
timestamp: January 14, 2024, 09:29:28 pm
content: This was also necessary, otherwise most current clamps would not have fitted.

author: Martin72
author_rank: Super Contributor
timestamp: January 14, 2024, 10:25:24 pm
content: Finally, a few measurements with the square wave function of the SDG1122X.The phase shifts correspond well with what you could see on the bodeplot.At 1Mhz you can see overshoots in the micsig, I think this is due to the impedance of 1M Ohm.The Tektronix is clearly ahead in terms of signal fidelity.I will soon be taking measurements in the "practicable" range, i.e. up to 500kHz, roughly the maximum switching frequency of appropriately constructed power supplies.

author: Martin72
author_rank: Super Contributor
timestamp: January 15, 2024, 10:30:31 pm
content: I am now in contact with Micsig.They wanted more pictures or even a video of how I measured it.Because I had asked them how they had carried out their measurements in order to achieve such a smooth linear curve.The vertical scaling with 0dB alone cannot be right.And they promptly asked back why I was in the mid -30db range...instead of telling me how they had measured it.Anyway, I took new pictures today and to show them that it can hardly be due to my setup, a new measurement with my tektronix A6302 and then another direct connection.Let's see what they say.In addition, I will soon be able to measure another "reference".I have ordered a siglent CP6030 current clamp for work...

author: amar87
author_rank: Regular Contributor
timestamp: January 17, 2024, 12:55:21 pm
content: they also told me the same thing.... to make a video sadly i had no time to do this maybe next week it gets better.

author: Martin72
author_rank: Super Contributor
timestamp: January 17, 2024, 09:30:36 pm
content: But I don't know why they want a video.I think the pictures are enough.Both current clamps have the same behavior.Both current clamps come from different suppliers.The setup is pretty much the same for both - well, then you could argue that you're doing something wrong.However, the significantly better behavior of the Tek probe with the same setup speaks against this.Micsig has not contacted me again after the other pictures, perhaps they are trying to recreate it themselves.Next weekend I will make more practical measurements, these bandwidth measurements are more of academic interest.

author: Martin72
author_rank: Super Contributor
timestamp: January 19, 2024, 09:59:30 pm
content: Still no answer from them...Before starting new measurements, I took two other tek probes from work to home and compared them with my private one.A nice to know, not more..

author: earthwormjim
author_rank: Newbie
timestamp: January 24, 2024, 05:52:23 pm
content: Quote from: Martin72 on November 20, 2022, 11:57:25 amThe CP6030 is not Hioki. It is made by Cybertek, Cybertek HCP8030 is the equivalent. People keep mistakenly attributing these probes to Hioki despite nothing in Hioki's lineup matching.http://www.cybertek.cn/info/989

author: Martin72
author_rank: Super Contributor
timestamp: January 24, 2024, 09:32:42 pm
content: Thank you for pointing that out, now some things are making more sense.Then we also have the 500A current clamp from them, which is really good, I'm looking forward to the "Tek Clone" which should be here next week.Speaking of which:Next weekend I'll take a few more measurements, then I'll make the preparations to send it back.Micsig didn't get back to me after I provided them with info and pictures, also they didn't answer my repeated request for their measurement setup, somewhat unprofessional behavior.Somehow I am still tempted to test the 50Mhz version, perhaps the 100Mhz is too "ambitious" for the circuit (the entire measuring electronics are in the clamp), but in the moment my motivation is a little bit low.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: January 25, 2024, 05:08:40 pm
content: Quote from: Martin72 on January 24, 2024, 09:32:42 pmMicsig has a rep here on EEVblog, he is quite a frequent visitor & solid to the bone - when he says something or merely indicates it, he / Micsig certainly delivers...

author: Martin72
author_rank: Super Contributor
timestamp: January 25, 2024, 06:31:32 pm
content: I can keep the current clamp for a few more days....

author: Martin72
author_rank: Super Contributor
timestamp: January 27, 2024, 12:21:33 am
content: The housing arrived "yesterday" and I have now built myself a better adapter.I will test it later with the Bodnar pulsers, a short Bode measurement showed no significant differences to my previously built adapter version.Edit:As I´ve used the micsig first with this adapter, I´ll connect its usb power cable to my scope insted using the AC adapter.Not a good idea:The range button flashes, DC offset about 3V was visible and no other actions possible.Then changed to the original AC adapter, everything works fine.

author: Martin72
author_rank: Super Contributor
timestamp: January 27, 2024, 08:48:23 pm
content: With my newly built adapter, the risetime drops to under 750ps (previously around/over 1ns) - I wouldn't have thought that.But that didn't do anything for the Micsig (pic 57 shown as ref A, both 10mA/div).Even if you switch to 5mA/div on the Tektronix, the good display is retained (pic58).If only the amplifier wasn't so huge, I would never think of getting another current clamp.

author: Martin72
author_rank: Super Contributor
timestamp: January 29, 2024, 05:31:15 pm
content: Hi,In the next few days I´ll send the probe back, I ´ve made some other measures, they looked ok.So my verdict:+Form factor, small builded+Building quality+High bandwith+Degaussing function+relative low noise-Measure resolution-Bandwith linearity-PriceIn my opinion, the last point is the most important.Even back then I didn't understand why the version with the normal BNC connection costs twice as much.The current clamp themselves are the same.So I would say that if the CP1003B cost exactly the same as the non-B version, it would be a good current clamp for the money (if you ignore the non-linearity).As it is, however, it is definitely overpriced and what is also a pity is its measurement resolution, which only provides usable results from 20mA/div.Once again, the old Tektronix A6302/AM503 combination has shown that it can't be beaten.I am still waiting for an affordable alternative, unfortunately the Micsig is not it.Martin

author: DaneLaw
author_rank: Frequent Contributor
timestamp: January 29, 2024, 09:40:07 pm
content: Quote from: Martin72 on January 29, 2024, 05:31:15 pmWasnt the price-drop on the non-B variant, down to a clearance sale, as it was founded on a dying interface standard, hence Micsig's UPI (Universal Probe interface) and only very few Micsig scopes from a certain production run, that lasted a short while had that UPI interface, as even Micsig own scopes, dropped it.https://eleshop.eu/micsig-cp1003-current-probe.html

author: Martin72
author_rank: Super Contributor
timestamp: January 29, 2024, 09:45:24 pm
content: Your link is showing the original price, it was drastically reduced during the sale, to half the price if I remember.Edit:It was 41% off:https://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5091109/#msg5091109

author: Martin72
author_rank: Super Contributor
timestamp: January 30, 2024, 06:37:05 pm
content: Today the CP6030 from Siglent arrived for work, let's see how it performs, it's quite a bit more expensive.

author: alm
author_rank: Super Contributor
timestamp: January 31, 2024, 06:52:42 am
content: Quote from: Martin72 on January 29, 2024, 05:31:15 pmThanks for your review! In terms of size, how does the size of the probe head compare to the Tek A6302? Can the Micsig probes fit a smaller wire loop? Because that's the place where I'm most often size-constrained. I'd love a DC-50 MHz probe the size of a Tek P6022 (an AC-only probe), but I don't think that exists. All competitors I've seen have a larger head than the A6302.

author: Martin72
author_rank: Super Contributor
timestamp: January 31, 2024, 08:07:38 am
content: Hi,I've made a pic, will post it later.

author: tautech
author_rank: Super Contributor
timestamp: January 31, 2024, 08:48:51 am
content: Quote from: alm on January 31, 2024, 06:52:42 amtautech hugs his P6021 and P6022 close.Decades since their release they are still the standard all are compared with.

author: alm
author_rank: Super Contributor
timestamp: January 31, 2024, 11:43:06 am
content: I agree it's impressive. The Tek P6042, which is essentially the same probe that they're still selling today, was introduced in 1967, although I think the later amplifiers like AM503A/B were a bit less drifty. And I still don't think it's been surpass in size or noise level. The only thing that was improved was bandwidth which only helps for some circuits (like those 500 MHz passive probes).

author: Martin72
author_rank: Super Contributor
timestamp: January 31, 2024, 06:48:53 pm
content: Size comparison....For the siglent CP6030 I´ll open a new thread, one thing:The noiselevel is very good...

author: Dennis Frie
author_rank: Contributor
timestamp: September 19, 2024, 07:36:19 pm
content: I was debating whether to buy the Siglent CP6030 or the Micsig CP503B current probe. Considering the price-tag of the Micsig CP503B probe, I decided it was still an interesting probe, even with the linearity issues.I have to say, so far the noise and DC accuracy is pretty damn good.I've played around a bit with the frequency response, trying to measure it at slightly higher currents. Still pretty bad compared to the specs as shown previously in this thread, but overall not a bad current probe the price considered. Compared to the 100 MHz model tested earlier in this thread, I see no reason to buy the 100 MHz as the linearity problems seems comparable.I will probably stick to the Lecroy CP030 probes for high-frequency stuff, but a great probe for a lot of other things.

author: Dennis Frie
author_rank: Contributor
timestamp: September 19, 2024, 07:49:20 pm
content: Direct comparison of the measurement Martin72 did.Same scaling on the y-axis, but tested with higher current. Considering I get significantly better linearity with a 50 Mhz probe, I either got lucky with the probe or the higher current makes a difference.Yellow = Martin72' original testGreen = my trace copied into the imageTested with 5 Vpp, 25R load (50R external + 50R internal in scope) and 3 turns on current probe. Gives approx. 400 mApp @ 1 kHz

author: Martin72
author_rank: Super Contributor
timestamp: September 19, 2024, 09:23:13 pm
content: Hi,That looks better, but if this behavior only occurs at higher currents, it's still not for me.Apart from that, I'm disappointed with Micsig's support; they never got back to me.No, I'll wait until I can afford the Siglent Current probe:https://www.eevblog.com/forum/testgear/siglent-cp6030-current-probe-a-very-very-short-review/msg5352083/#msg5352083Until then, I'm doing fine with my Tektronix A6302...

author: Dennis Frie
author_rank: Contributor
timestamp: September 20, 2024, 11:07:47 am
content: Quote from: Martin72 on September 19, 2024, 09:23:13 pmYeah I did consider the Siglent CP6030 after reading your tests. No doubt it's a better probe, but it also comes at a significantly higher price.I think the Micsig probe has its place, but the datasheet specs and graphs are misleading.

author: folays
author_rank: Contributor
timestamp: October 25, 2024, 03:10:55 pm
content: Hi, I've bought a brand new CP503B, is having only XX mA precision on a constant DC 30V / 2A normal ?Here below are the probe in the 6A range (correctly in the lock position !) when power supply is OFF, then ON.As you will see, under 2A of current, the probe measures an AMPLITUDE of 237 mA(24 mA at rest).Should I send back my probe ?I've bought it at Jeulin because 2 days ago Batronix didn't have it in stock, maybe I should have asked and waited...The Datasheets (https://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5260149/#msg5260149) says :Code:DC accuracy : ±1%±10mA (6A)(for info, under the 30A range, the "imprecision" (Amplitude) would jump from 237 mA to around 440 mA.Previous forum user herehttps://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5259840/#msg5259840shows it had (albeit at a much reduced voltage, possibly from an AC source) a Pk-Pk of 10 mA, whereas even under NO LOAD I still have much worse Pk-Pk of 24 mA.Here below is the setup of the lab power supply + the DC electronic load (which I put on a constant RESISTANCE).Maybe I misunderstood the ability of the DC load to really maintain a stable resistance (or current) under a stable power source ?For the sake of checking with a constant CURRENT setting on the DC load (no photo included, but I set the DC load on CC 2A "in the 5A and 36V range") :Much better, 175 mA of Amplitude, but it seems way off the Datasheet precision (±1%±10mA) which should have yield a measured amplitude precision of 30 mA max ?Thanks & Best Regards,

author: Martin72
author_rank: Super Contributor
timestamp: October 25, 2024, 03:42:25 pm
content: Hi,https://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5275105/#msg5275105See the noise picture, try to recreate it with the settings you can see in the picture.Then:You're not triggering on channel 4, I'd change that if I were you.

author: Kean
author_rank: Unknown
timestamp: October 25, 2024, 03:57:43 pm
content: Quote from: folays on October 25, 2024, 03:10:55 pmDo you have a 15 ohm 100 W resistor by any chance? That way you can eliminate any extra noise induced by the DC load control loop. You've already shown CR is noisier than CC mode.You can use use a lower voltage if you only have lower wattage resistors. It also doesn't have to still be 2A to get a feel for if it makes any difference.Even better if you can use a battery as the source.

author: electr_peter
author_rank: Unknown
timestamp: October 25, 2024, 04:21:19 pm
content: Quote from: folays on October 25, 2024, 03:10:55 pmCC mode works best, other modes (CR/CV/CP) are "indirect" with most DC loads and can produce "interesting" results.Bottom line, use very stable current source (real resistor across PSU output) when checking stability of current probe.

author: folays
author_rank: Contributor
timestamp: October 25, 2024, 09:32:22 pm
content: Thanks for you insights ;I'm new to the electronic hobby ; See one of my adventure here :https://www.eevblog.com/forum/repair/repairing-a-robotic-pool-cleaner-zodiac-vortex-3/In the above topic, for a pool cleaner robot, the propeller motor is powered at 28V and I measured the propeller motor at around 56 Ohm (disconnected, at idle).On my desk (above water) The robot would put itself in a state of "fault" mode, and I guessed that the IC board were measuring propeller consumption Amperage,and thus was able to put itself to fault mode for safety reasons, thinking it somehow got out of the pool.The future (yesterday) proved me right, as soon as I plugged a DC load consuming those 28V at 20-25 Ohm or less (raising Amperage to 1.5 A), the robot behaved like it were submerged.I often told myself, as in the case above, "damn right now I would like to have a purely resistive load, 28V at 1-2 Ampere in this case, so I would need something around 20 Ohm, not the most difficult I have a box of resistances, but I mainly need it to be able to dissipate 14 Watts of energy, not those pesky .125 Watts common resistances... Welp, let's buy a DC load....".As a newbie, I only used for now Batronix and Eleshop, but they don't have neat low-resistance multi-watts resistances.Would you have a shop recommandation for Europe/France ?Unfortunately, on the supply side, I don't see where I could at home find 1A ofbatteryDC current. Car's battery I would prefer not extracting it (car electronics sometimes reset unwanted stuff like remote keys), Power tools' batteries have circuitry unless I open their assembly, maybe I could take a bunch of AA batteries in parallel, I didn't checked their per-unit Amperage.In the post linked by Martin72, I see the user have ahttps://www.siglent.eu/product/1149228/siglent-df2001a-power-analysis-deskew-fixture.It's probably off-topic and of no help, but in any case, I own the Batronix Demo boardhttps://www.batronix.com/shop/demoboards/Batronix-MSO-Demo-Board.html.QuoteI wanted to be in roll mode (continuous and rolling, not clearing-the-screen every time the horizontal span of time has been measured), I didn't yet figured out how to make Roll mode always behave like this, but I think that if I were to be (a) in Roll mode (b) set a correct channel (c) have the trigger level in the Amplitude region ; Then I sometimes have the Roll behaving like if the scope were to be in "Normal" mode (not "Auto" neither "Single") and not really "rolling", so until I understand why, when I want to "roll", I either set the wrong channel or set the trigger level outside of the Voltage amplitude.Anyway, below are more refined scope settings, trying to copy Martin72's settings ofhttps://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5275105/#msg5275105:I changed the Timebase, Martin72 was at 1ms/div, I set my scope to 50us/div, and trigger to C4 "Normal" ;Picture 1 and 2 are the same (just letting you on the (1) see the Channel settings, DC mode and BW 20M limit mode).Picture 3 is at 10us/div.I don't known why the "bands" are so much wide (multi-pixels height), I didn't enabled "Persistence" or something like that.The Amplitude stills shows 144 mA.Question is, regarding the Amplitude variation (which should be 2A stable in non-existing ideal setup), but is 144 mA which instruments are guilty ?(a) could it be partly the CP503B but only for partially for up to 20-30mA variation ?(b) the lab PSU and the DC load ?Bonus question : I think that even if non-ideal, considering that the lab PSU is probably waaay less noisy than the DC load, would I be right regarding the lab PSU (SPD4036X)noisefor being nearly non-existing (for being 10x much lower than the noise of the DC load), at least util then DC load is replaced by a "pure resistive load" ?The amplitude is really sinusoidal-alike at 24k Hz, but I'm not knowledgeable enough to extract information from that.I'm in Europe so mains is at 50 Hz (not 60), scope is 1 Ghz capable, CP503B should be able to measure up to 50 Mhz, at least 10 Mhz without huge distortions...What I am observing here ? some ripple of the DC load ? What should I prioritize, finding a low-resistance 100 W ?I own a broken 1000 Watts mains (230 V) resistive heater awaiting diagnostic. The resistor inside it should be around 50 Ohm I guess? And be able to dissipate... Maybe I should try that ?Thanks & Best Regards,EDIT : upload missing images.

author: folays
author_rank: Contributor
timestamp: October 26, 2024, 12:39:29 am
content: Hello again, I salvaged a mains' heater 1000 Watts measured at 55.32 Ohm, so around 0.54 Ampere for the same 30 V.Below two capture, I set the DC load (Siglent SDL1020X-E) to the same CC than expected heater's resistor (0.55 A).(again I moved the trigger out of the voltage level, I didn't want to post-analysis, so I wanted the scope' to roll freely)First one shows the DC load, 62 mA of Amplitude (and Pk-Pk).Second picture shows the pure resistive load, 11.294 mA of Amplitude (and Pk-Pk).Sorry for the disturbance, it was the DC load, the CP503B works better without an electronic DC load.Best Regards,

author: Martin72
author_rank: Super Contributor
timestamp: October 26, 2024, 02:03:09 pm
content: Hi,I can confirm that there is a small ripple:https://www.eevblog.com/forum/testgear/accurate-low-amp-current-probe-advice/msg5690313/#msg5690313

author: Kean
author_rank: Unknown
timestamp: October 26, 2024, 03:16:12 pm
content: Quote from: folays on October 26, 2024, 12:39:29 amGreat! I was just reading your earlier post and thinking to ask if you had a hair dryer or small fan heater you could check for resistance.Some years ago I bought a handful of 50W and 100W power resistors in values like 1, 3.3, 5, 10, 22, 47, and 100 ohm, and mounted some on various heatsinks. I have at least 6 programmable DC Loads and a few 2/4 quadrant power supplies, but a simple resistive dummy load can be very handy.I have picked up some surplus resistors very cheaply over the years. I think a large bag of 22 ohm 3W and tray of 10 ohm 25 W resistors have proved particularly handy. I can wire these up in various series/parallel combination to make different loads.A hot water heater element I bought was not expensive and turned out to be about 16 ohms and can run several kW in a bucket of water. I've been planning to buy another to get 8 ohms.These resistors can have some inductance that should be taken into account depending on what circuit you connect them to.

author: electr_peter
author_rank: Unknown
timestamp: June 17, 2025, 10:19:50 pm
content: Micsig changed form factor (and improved specs) of CP503B/CP1003Bhttps://www.micsig.com/list/460This could explain a slightly better performance in later posts here.Quote

author: Martin72
author_rank: Super Contributor
timestamp: June 17, 2025, 10:33:27 pm
content: The problem was more the miserable linearity above 1 MHz.

author: electr_peter
author_rank: Unknown
timestamp: June 18, 2025, 09:59:21 am
content: Maybe noise is lower, but linearity is still terrible. Performance doesn't justify the price.

author: kud_
author_rank: Newbie
timestamp: August 19, 2025, 09:32:19 am
content: I was thinking about buying it, but since it is what it is...What would you suggest as a alternative that is cheap and good for hobby use? Bandwidth around up to 10MHz.Now i have to options:a) get something cheap from probably China. Is there anything worth looking?b) building something of my own, i did quick investigation and worked in the past with LEM's. Also i saw some cheap TMR sensors that i can use (no insulation then :'()