Current Probe

[Hacked]

Hello all,

I am looking to buy current probe for my analog discovery 1 (I will probably buy new scope next year)
I would mostly use it to hobby design smps and audio electronics.

Was looking at micsig current probes:
Micsig-CP2100A
https://www.batronix.com/shop/measurement/probes/Micsig-CP2100A.html

Micsig-CP2100B
https://www.batronix.com/shop/measurement/probes/Micsig-CP2100B.html

Micsig-CP503B
https://www.batronix.com/shop/measurement/probes/Micsig-CP503B.html

CP2100A has smallest bandwidth (800kH), but I remember that I was reading here that most CP2100A has better bandwidth than declared, closer to CP2100B. Don't know if this is still true.
Micsig-CP503B has best specs but also significant price increase
Would CP2100A be enough to see switching currents in 100kHz range?

Best Regards

[Martin72]

Hi,

Since their bandwidth does not stop abruptly at 800khz, this should not be a problem.*
It is important to know that the CP2100 is not so well suited for very low currents, which is not surprising with a 100A clamp.
I had both 2100s and I think the price/performance ratio is very good.
But they are not exactly small.
My test thread:
https://www.eevblog.com/forum/testgear/micsig-current-probe-cp2100b-tests-and-comparing/msg3063816/#msg3063816
I had also tested the CP503B:
https://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5275105/#msg5275105

Martin

*)The bandwidth of a measuring device should be significantly higher than the signal to be analyzed.
Example from practice:
Investigation of a power PWM with 16khz, using the AP011 from lecroy as the current clamp.
This had a bandwidth of 120kHz, the signal looked different than expected, with a Tektronix current clamp (2Mhz) the signal curve was as expected.

[bdunham7]

The inputs of the Analog Discovery are fully differential if you don't use the BNC adapter, so as long as you observe the modest common mode voltage limits you can just use an appropriately sized resistor as your current probe.

[Hacked]

I know that, but that's a hassle.
And without BNC adapter analog discovery 1 range isn't to big (+/-25V).

[Hacked]

Hi,

Since their bandwidth does not stop abruptly at 800khz, this should not be a problem.*
It is important to know that the CP2100 is not so well suited for very low currents, which is not surprising with a 100A clamp.
I had both 2100s and I think the price/performance ratio is very good.
But they are not exactly small.
My test thread:
https://www.eevblog.com/forum/testgear/micsig-current-probe-cp2100b-tests-and-comparing/msg3063816/#msg3063816
I had also tested the CP503B:
https://www.eevblog.com/forum/testgear/micsig-cp1003cp503-100mhz50mhz-current-probe/msg5275105/#msg5275105

Martin

*)The bandwidth of a measuring device should be significantly higher than the signal to be analyzed.
Example from practice:
Investigation of a power PWM with 16khz, using the AP011 from lecroy as the current clamp.
This had a bandwidth of 120kHz, the signal looked different than expected, with a Tektronix current clamp (2Mhz) the signal curve was as expected.

So from your reviews I see that you are satisfied with CP2100B, but not with CP503B?
Is CP503B worth almost double money than CP2100B?
It has 50MHz bandwidth so that should be more than enough for switching on/off currents in smps?
Or is better to just buy CP2100B.
Damn, don't know what to buy

[Martin72]

Hi,

So from your reviews I see that you are satisfied with CP2100B, but not with CP503B?

Yes and no.
The CP2100B costs little but offers good performance.
The CP503B is not bad, it has much less noise than the CP2100 and is therefore also suitable for lower currents.
Its significantly smaller size is also an advantage.
But it has an unstable bandwidth and is quite expensive compared to its performance.
Or let's put it another way:
For the money, I would rather buy a used combination from Tektronix (A503/A6302), which is simply incomparably more stable in terms of values.

It has 50MHz bandwidth so that should be more than enough for switching on/off currents in smps?

Absolutely.

[Hacked]

What about this probe?
https://de.aliexpress.com/item/32881821930.html?spm=a2g0o.productlist.main.1.7c6e0oZF0oZFwI&algo_pvid=41e89346-20e8-4185-8713-9c03edf85ced&algo_exp_id=41e89346-20e8-4185-8713-9c03edf85ced-0&pdp_npi=4%40dis%21EUR%21912.18%21857.45%21%21%21954.06%21896.82%21%402101eac917144780287093332ea0f8%2165582139153%21sea%21NL%212384545467%21&curPageLogUid=O7oVUmnbg0AU&utparam-url=scene%3Asearch%7Cquery_from%3A

With discount it's 700€, which is great price if it works without problems.

How does it compare to CP503B? I see you use both probes.

From what I saw CP503B has problems with linearity above 10MHz, but ICP5025 does not.
Both are similarly priced, Micsig is 50€ more.
What probe would you recomend, ICP5025 at 700€ or CP503B at 750€ ?

[Hacked]

Hi,

So from your reviews I see that you are satisfied with CP2100B, but not with CP503B?

Yes and no.
The CP2100B costs little but offers good performance.
The CP503B is not bad, it has much less noise than the CP2100 and is therefore also suitable for lower currents.
Its significantly smaller size is also an advantage.
But it has an unstable bandwidth and is quite expensive compared to its performance.
Or let's put it another way:
For the money, I would rather buy a used combination from Tektronix (A503/A6302), which is simply incomparably more stable in terms of values.

It has 50MHz bandwidth so that should be more than enough for switching on/off currents in smps?

Absolutely.

Sorry to bother you, but I saw that you used both the micsig cp503 and ICP5025, which probe would you recommend more? They are both priced close, micsig probe is 50€ more.

[Martin72]

Hi,

What probe would you recomend, ICP5025 at 700€ or CP503B at 750€ ?

Between the two, I would prefer the CP503B.
The workmanship and general quality is much better and you at least have some kind of support because Micsig is a fairly well-known brand.
The non-linearity around 10Mhz will not play a role in practice in the vast majority of cases.

Martin