Micsig CP1003/CP503 100MHz/50MHz Current Probe

[EEVblog]

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

[Martin72]

Could sell the 50MHz version for under USD$500

 

Are you sure ?
EDIT:

Talking about prices

[EEVblog]

Could sell the 50MHz version for under USD$500

Are you sure ?

Yep. They have already given me a 50qty price.

[Martin72]

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.

[EEVblog]

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.

I 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.

[Psi]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

[Martin72]

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...

I can ship to Germany.

Pls pm me when you can do it.

[tautech]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

Do you need one ?
I think we have some 200A probes left.

[EEVblog]

Pls pm me when you can do it.

I 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...

[EEVblog]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

I guess that's possible. Never tried it myself.

[Martin72]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

We 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)
To simulate more current as you got you turn multiple wires to the core.
To measure more current than your probe can, you use a divider.

[tautech]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

I guess that's possible. Never tried it myself.

It'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.

[EEVblog]

Do you think it's feasible to make up a cable with thinner wire loop across it to turn the 30A range into 300A?

I guess that's possible. Never tried it myself.

It'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.

No, 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.

[Martin72]

See my last post here.

[nctnico]

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.

I 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.

I 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.

[Hydron]

<$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.

[nctnico]

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.

[Martin72]

<$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.

It 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...

[electr_peter]

On Saelig 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.

[EEVblog]

On Saelig 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.

Sounds like I'm going to own the market then 

[EEVblog]

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?).

Yes. 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.

[Martin72]

Price difference makes no sense to me, because B version just has different form factor with same specs.

Look 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 ?

[EEVblog]

Price difference makes no sense to me, because B version just has different form factor with same specs.

Look again....
One fits only in micsig scopes, the other(B) is universal for all scopes.
Dave:
Which version will you get ?

The B version for all scope of course. Practically zero market for a Micsig interface unit.

[Martin72]

Hm...

Practically zero market for a Micsig interface unit.

Therefore it makes sense when this version is cheaper...or not, I´m a little bit confused.

https://www.saelig.com/micsig/cp503b.htm

They 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

[nctnico]

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?).

Yes. 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.

I 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.

[tomud]

I 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.

Hmm, 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.

[electr_peter]

Price difference makes no sense to me, because B version just has different form factor with same specs.

Look again....
One fits only in micsig scopes, the other(B) is universal for all scopes and got dedicated circuits for it.

Both 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 with DP750.

However, adapter PA05 is 5V 1A, but required power is 5V 3A. No official adapter is available at this point.

[Martin72]

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

[Martin72]

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)

[Martin72]

After request, batronix will offer the probes also and because they´re in germany, I´m probably out...

[Martin72]

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

[EEVblog]

But the main thing is, look at their prices....

That's the kicker. Still I bet a lot of people will say they are expensive.

[Martin72]

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.

[Martin72]

Anything new here?

[jonpaul]

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 check

3 db BW, (not 6 db!) rise time,pulse abberation ( overshoot)
DC offset adjustment,degauss  effectiveness, DC drift with warmup and temperature
CMRR eg with 500V H bridge wire the fast rise on the probed wire will couple into the currency probe
Easy 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 pinout

So,  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 EE

Jon

[EEVblog]

Anything new here?

Haven't heard anything.

[Martin72]

Meilhaus electronics have listed the probes:

https://www.meilhaus.de/en/micsig-cp-hf.htm

1178€ (incl VAT) for the CP503B...
And nearly the half for the Non-B version....

And eleshop also:

https://eleshop.de/micsig-cp503b-current-probe.html

Same 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..

[Martin72]

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...

[jonpaul]

For 600..1200 EU you can get a very fine TEK vintage probe with amp.

Check epay for Tektronix current probes

Jon

[JPortici]

But the main thing is, look at their prices....

That's the kicker. Still I bet a lot of people will say they are expensive.

people that are used to cheap crap you can "hack"?

[Fred_47]

No, 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.

There 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.

[Martin72]

For 600..1200 EU you can get a very fine TEK vintage probe with amp.

Check epay for Tektronix current probes

Jon

Yes 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 probe

Rigol probe

R&S probe

Lecroy probe

And 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. 

[PartialDischarge]

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.

[EEVblog]

Plus I really do not understand why the universal "B" variant costs twice as much as the one for micsig scopes only. 

It shouldn't from what I've been quoted wholesale pricing for the B varient.

[jonpaul]

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/Dt

In 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

[jonpaul]

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 mm
Cap 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,

Jon

PS:
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 P6022

PPS: Yokogawa current  probes are also excellent but the probe power  is a proprietary pinout, +/- 12 V on a 4 pin Lemo.

[PartialDischarge]

In 55 yrs we never had a problem with a current probe CMRR.

Never 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.

Conclusion: CMRR is not an issue, external Faraday shield unneeded.

Wrong 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.

[thaamike]

Any luck getting these probe for the nice price ?

[EEVblog]

Any luck getting these probe for the nice price ?

I've just asked again for the sample.

[EEVblog]

Any luck getting these probe for the nice price ?

I've just asked again for the sample.

They got back to me. The R&D team are all working on the isolated probe and have no time to finish the current probe  so 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.

[nimish]

Any luck getting these probe for the nice price ?

I've just asked again for the sample.

They got back to me. The R&D team are all working on the isolated probe and have no time to finish the current probe  so 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.

If you can sell it for less than $10000 yeah. IsoVue probes are not cheap to replace...

[mawyatt]

Any luck getting these probe for the nice price ?

I've just asked again for the sample.

They got back to me. The R&D team are all working on the isolated probe and have no time to finish the current probe  so 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.

This 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,

[mk_]

This 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?

 

We probed a shunt riding on a 25kHz 700V Output (square, not sinus) with an early https://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.

[nimish]

This 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?

 

We probed a shunt riding on a 25kHz 700V Output (square, not sinus) with an early https://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.

It's a little ridiculous honestly. Makes one want to try to DIY a probe using https://docs.broadcom.com/doc/AFBR-POCxxxL-DS or something. I'd rather spend $3000 than $7500+ to get isolated HV gan/sic measurements

[Alphaprot]

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.

[Martin72]

Or let me think about what´s in the box...
Batronix still doesn´t offer them.

[EEVblog]

This 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?

They contacted me again recently, one is apparently on the way.

[Bran Zhu]

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.

[Durong]

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.

[gossamer]

I wonder if cp503 would work with this upi to bnc adapter. Or is there something else significantly different between 503 and 503b ?

[Martin72]

Short review:

[Someone]

Short review:

Much 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.

[Martin72]

Much more than "short" !

Yepp...

Noise performance is impressive for such low cost.

Unfortunately 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....

[dirtcooker]

I wonder if cp503 would work with this upi to bnc adapter. Or is there something else significantly different between 503 and 503b ?

The 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.

[dirtcooker]

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 $100
https://www.sainsmart.com/products/micsig-rcp500-rogowski-ac-current-probe-300khz-with-standard-bnc-interface

[DaneLaw]

I wonder if cp503 would work with this upi to bnc adapter. Or is there something else significantly different between 503 and 503b ?

The 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.

I 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/6zkhze47
though 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/3v5v6a47
I 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

[LTXAPAS]

I wonder if cp503 would work with this upi to bnc adapter. Or is there something else significantly different between 503 and 503b ?

The 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.

Has anybody tested the CP503 with the accessory in a normal oscilloscope? (using the right voltage)...

[gossamer]

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

[DaneLaw]

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

Micsig 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..)

[Martin72]

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

And one shop offers the Non-B probe for 41% off...

https://evision-webshop.de/micsig/cp503-strommesssonde

344€ incl. VAT/486€ for the CP1003....

[amar87]

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.

[Martin72]

Do it please...
Noise, bandwith, accuracy....

[amar87]

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.

[amar87]

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 supply   





Test Setup for Accuracy 30 A range :

same as 6A range   




I 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

[Martin72]

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/#msg3366960

In 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/#msg3072460

May I ask what you´ve paid for the micsig probe?

[amar87]

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 .
 

[Martin72]

Hi,

Test Setup for Accuracy 6 A range :

- same as above + the following:
- DC electronic load
- Fluke 8846A Multimeter (not calibrated)

If 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

[amar87]

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.   

[Martin72]

Also the reason for not testing over 6 A is that i have no power supply that provides more than 6A.   

You 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.

What confuses me here is the spec of +/1%+/-10mA(6A Range)

For me it reads as +/-1%, but at least +/-10mA.

[_Wim_]

For me it reads as +/-1%, but at least +/-10mA.

I 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.

[_Wim_]

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.

This 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.

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....

I 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.

[amar87]

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 lower


Having  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

[amar87]

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 25Mhz




Here 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.

[Martin72]

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.

[_Wim_]

The requested screenshots with 20 Mhz bandwidth:

6A range :
(Attachment Link)

30A range 100 ms/div  :

(Attachment Link)


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 lower


Having  20 ms/div i get this :

(Attachment Link)



Then 20 ms/div and change aquisition to average i get this:

(Attachment Link)


So i don't know how to measure to verify the ≤ 1.4 mA RMS (Bandwidth at 20 MHz, Range 30A, 10X) spec

I 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. 

[amar87]

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. 

[Martin72]

Hi,

I can use my siglent scope on the FFT function (hope it has MAXHOLD)

Has it:

https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-12bit-(published-for-chinese-domestic-market-only)/msg5213874/#msg5213874

[Martin72]

Hi again,

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.

This 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.

[Martin72]

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.

[Martin72]

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

[Martin72]

Last pic.

[cameronb]

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 inside
  GDE232E (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 GDE232E
 
As 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.

[cameronb]

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.

[amar87]

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 ... 

[idolclub]

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 .

The maximum power consumption of CP1003B is about 5V / 800mA, typical 400mA.

CP1003B also can work with Apple or Samsung 5V / 2A charger.

[amar87]

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 inside
  GDE232E (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 GDE232E
 
As 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.

If you have the time could you also try to do same experiment as Martin and me and report back the result?

[Martin72]

I tried some more experiment:

I 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.

[_Wim_]

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 ...

I 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?

[_Wim_]

One more question, are you sure the slider is fully closed (should be in the "lock" position to measure)

[Martin72]

Woah, Eagle-Eye! 



It could be, no, it will be.

[amar87]

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.

 

[Martin72]

Please do that, the Micsig is still of interest because it is simply very compact compared to a Tektronix combi.

[amar87]

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' BNC





We 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 RG58



The response i a lot flatter.

[amar87]

I wanted to see what happens if the probe will just stay on the coax.... so don't ask why



Something weird happens now this is a scope problem but however maybe it give a clue on the issue

Ran 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.

[amar87]

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.

[amar87]

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.

[Martin72]

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.

[amar87]

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..... 

[amar87]

how to place the pictures so they open inline (sorry for the forum-noobness)?

[Martin72]

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.

[Martin72]

how to place the pictures so they open inline

One possibility is to use the default setting (end of post expendable thumbnail).

[amar87]

Before i put the setup away i thought i would do some pulses through it and see what it does. 

they say Delay ＜ 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?

[amar87]

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...

[Martin72]

Ah, very good.
Do you have access to a (very)fast risetime pulse ?

[amar87]

what you see there in the rigol screenshot the 7 nS is the fastest i have......

[Martin72]

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.

[_Wim_]

I wanted to see what happens if the probe will just stay on the coax.... so don't ask why

(Attachment Link)

Something weird happens now this is a scope problem but however maybe it give a clue on the issue

Ran the bode plotter 2 times first run gives this:

(Attachment Link)

Second run:

(Attachment Link)

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.

I 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...

[Martin72]

My previous "only cable test" I did several times, always with the same result.

[amar87]

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.

[Martin72]

I have just asked Batronix if they would lend me a CP1003B for testing.

Not, but they suggested to "buy" it and return inbetween 30days.
And that´s what I did, should arrive in the next days.

[Martin72]

Batronix, fast as lightening, as ever...

[amar87]

Cool! Let's see how it tests. 

[amar87]

did yours come with an EU style power adapter?

[Martin72]

Hi,

Yes, with this one:

https://www.knivesandtools.de/de/pt/-qualcomm-qc-3-0-usb-adapter.htm

Let's see how it tests.

I'm also very curious, but I'll wait until tomorrow because the package was very cold.

[Martin72]

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.

[Martin72]

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.

[amar87]

So i was not crazy........ it happens as well at your side.

[Martin72]

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.

[amar87]

i love it how you dremeled the deskew fixture........

[Martin72]

This was also necessary, otherwise most current clamps would not have fitted.

[Martin72]

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.

[Martin72]

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...

[amar87]

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.

[Martin72]

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.

[Martin72]

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..

[earthwormjim]

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)

The 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

[Martin72]

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.

[DaneLaw]

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.

Micsig 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...

[Martin72]

I can keep the current clamp for a few more days....

[Martin72]

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.

[Martin72]

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.

[Martin72]

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
-Price

In 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

[DaneLaw]

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

Wasnt 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

[Martin72]

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

[Martin72]

Today the CP6030 from Siglent arrived for work, let's see how it performs, it's quite a bit more expensive.

[alm]

+Form factor, small builded

Thanks 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.

[Martin72]

Hi,

I've made a pic, will post it later.

[tautech]

+Form factor, small builded

Thanks 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.

tautech hugs his P6021 and P6022 close. 
Decades since their release they are still the standard all are compared with.

[alm]

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).

[Martin72]

Size comparison....

For the siglent CP6030 I´ll open a  new thread, one thing:
The noiselevel is very good...

[Dennis Frie]

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.

[Dennis Frie]

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 test
Green = my trace copied into the image

Tested with 5 Vpp, 25R load (50R external + 50R internal in scope) and 3 turns on current probe. Gives approx. 400 mApp @ 1 kHz

[Martin72]

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/#msg5352083

Until then, I'm doing fine with my Tektronix A6302...

[Dennis Frie]

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/#msg5352083

Until then, I'm doing fine with my Tektronix A6302...

Yeah 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.