EEVblog 1413 - Oscilloscope Current Probe TEARDOWN + DEMO

Teardown and measurements with the Micsig CP2100B 2.5MHz oscilloscope current probe.
Also a demonstration of mains switch mode power supply current and noise measurement, and also some performance tests.

Use the coupon code FLUX for 15% off!
And paying with crypto gets you a further discount on top of that!
Or get the cheaper lower bandwidth 800KHz CP2100A model:

00:00 - Intro
05:39 - Teardown of base unit
14:25 - Clamp unit teardown
23:40 - Mains switchmode current measurement
34:00 - Measuring the Earth's magnetic field!
34:42 - Noise measurement
35:26 - Low current measurement

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#ElectronicsCreators #Teardown #Review

[yuxianwang]

Well this is widely used in current sensing for hall sensor in parallel to cancel temperature coefficient. And I work for the company in the video. Max bandwidth we have now is 1-2mhz. And this not yet publicly available.

[dnbeuf]

Got it myself as well. Quite happy with it so far. For measuring low currents a wire can be passed multiple times through the clamp to increase sensitivity. Looping twice makes current readout twice as high, .. etc

[jenniferwhitewolf]

For decades I have used the Tektronix A6302 current probe (50MHz) with AM503 module. It is an amazing tool as a design aid when designing power supplies. I would not even think about designing a supply without being able to actually see such things as the transient current on the peak of voltage haversine charging filter capacitors. If you are even thinking of designing a power supply, first buy a current probe. This is an affordable and decent performing tool. Every lab needs one.

[voltlog]

The micsig probe beats the others on specs vs Price and build quality and I've been a happy user for a while now. Anyone doing these kind of measurements should get one!

[kreature]

The USB DC-DC is to isolate the supply from your oscilloscope.
Very good!

[TheDigitalAura]

Micsig seem to make some pretty good stuff, very happy with the 100mhz differential probes I bought.

[ulfg]

If you put it around the feed wire to the starter motor on a small multi cylinder engine (100A isn't enough for large engines), a motorcycle for example, and disable fuel or spark so the engine doesn't start you can do a relative compression test in seconds. The current goes up as the starter works against the compression in each cylinder, so you can determine if all cylinders are even or one has lower compression than the others.
Use it on any other brushed electric motor (such as a fuel pump) and you can see the current variation as the segments on the commutator rotates past the brushes, if brushes/segments are bad or a winding is toast it will be quite uneven while a good one should basically be a nice wave repetition.
You can see if an electromagnet moves something, as in a relay or fuel injector, the movement gives a hump in the current waveform.
You can identify coils (relay, fuel injector, ignition coils and so on) with partially shorted windings, as the current waveform will be different from a good coil.

A current clamp can be a fantastic diagnostic tool, even with far less bandwidth than a great one like this. I really have to get one soon - or a couple, for low & high current.

I dissected the PROVA CM05 current probe, and it also had two sensors mounted in opposite direction, and electrically chained in the same fashion.

[marcelhensen]

You need to hold the probe in the orientations it's going to be during the measurement as you are zeroing it. Otherwise you don't compensate for the earth's magnetic field.

[wearethewatt]

Dave, if your result is 42 then you dont need to regard fractional digits. Those are errors by definition as the exact answer is known.

[AHaensel]

"I haven't personally gone over 10 amps" - I think Photonicinduction may be able to help...

[rubusroo]

Really nice build quality too. Another great device I have absolutely no need for but will probably end up buying.

[robinbrowne]

It would be interesting to put the mains current on channel A, and the main voltage on channel B. Then multiply them with the scope maths to get the real power.

[davidjereb]

7:46 Having used an EFM8 chip before in a precision analog application, I strongly disagree. The internal ADC is as stable as a rock.

[MikelNaUsaCom]

In college, I worked on a battery powered pic micro-controlled 3 phase current monitor that turned on, took a reading then went back to sleep ... used a i2c dac and 3 external probes, ic2 memory. auto calibrate, set in the box, lock it up, come back in a few weeks and download the memory using RS232 to a pc and use excel for data analysis... bob's ur uncle. Great memories.

[KGJYS]

It's more like $510USD plus shipping with the coupon code. Hantek makes one that's not nearly as nice, but it's $54USD. Manual zeroing and 20khz limit. That's fine for what I bought it for. Those of us that have an entry level scope like a ds1054z probably balk at a probe that costs more than the scope.

[johnnyjoseph]

I use the A version of this and Micsigs ATO1104 automotive scope... Both are surprisingly well made and surprisingly inexpensive when compared to the stuff you buy off the tool trucks in the automotive industry.

[alessandroscroccaro]

I own the CP2100B micsig and I confirm that the bw -3dB reaches more than 2MHz (I measured the band) then the capacitive couplings weigh and therefore it is difficult to appreciate, but still a great result under 400 €.

[mxzhang]

The PSZQ is TPS7A30 low noise negative LDO

[falkkyburz]

Small clarification at 30:50: The current we are pointing at is most probably the X capacitor current which leads the voltage by 90°. Current to achieve PF~=1 would have to be in phase with the voltage (which we don't see). Even with a PFC, the X capacitor would mess up the PF with the added capacitive current.