Hantek CC-65 AC/DC Current Probe Teardown and Testing

[Mechatrommer]

quick and simple current measurement setup...
* poorman's FG 5.88Vpp sine wave into 52.88ohm (measured with DMM) load/termination
* dso channel 1 (yellow) is reading volt across load resistor.
* cc-65 probe setting at 1mV/10mA, plugged into channel 2 (blue) of dso.
* dso acquisition is averaged 8
* theoritically the reading should be (5.88Vpp/52.88ohm = 111mA, ie 11.1mVpp reading at channel 2)
* theoritical -3dB reading is @ 11.1mVpp / 1.414 = 7.86mVpp

result:
reading floor at 5mA (500uVpp), ie no current/wire pass inside hall sensor (refer to 4KHz open.png)
-3dB BW is excess of 23KHz, hence the claim in the spec (20KHz BW) is valid. (refer to 23KHz test 52.88ohm.png)

teardown pictures as attached...
http://www.dx.com/p/hantek-cc-65-ac-dc-current-clamp-meter-multimeter-with-bnc-connector-blue-black-197938#.VG4o3sZNJ8E

(edit 240411)
some useful posts (imho) to consider modding your probe: (please inform me if i miss other useful info) ymmv
1) mickab: https://www.eevblog.com/forum/testgear/hantek-cc-65-acdc-current-probe-teardown-and-testing/msg3320244/#msg3320244
2) toli: https://www.eevblog.com/forum/testgear/hantek-cc-65-acdc-current-probe-teardown-and-testing/msg3625496/#msg3625496

[bdivi]

Hello Mechatrommer,

Thank you for the mini review.

This Hantek clamp is one of the very few affordable DC milliamp clamps on the market and I bought myself one a couple of months ago.
I was however disappointed with the performance. As you noted AC is good to above 20KHz (I measured 28KHz -3dB). The clamp DC nulling on the other hand is hopeless - I have to press the button numerous times in order to get it close to 0 and after that it drifts all over . It goes +/- 50mA in several minutes and on top of that it measures 5-6% above the actual value.

I was in contact with Hantek support asking them for calibration/repair manual and schematic but could not get anything so far.

I am sure that if we get hold of the schematics we will be able to improve the performance - it is amazing how they managed to put so many low quality trimpots in this package.

Cheers
bdivi

[R_G_B_]

Best way to test this is to use a square wave. I think it works up to around 2khz square wave. Then it gets out of shape and distorts the amutude and phase response.

R_G_B

[Lightages]

I also have one of these and have been meaning to do a review of it too. Other things have gotten in the way. I also am not very impressed with the performance. I hold zero hope of getting any kind of help from Hantek, but you never know.

[IDEngineer]

Just picked up a Hantek CC-65 current probe. I'm working on some motor sensing circuitry and have a precise onboard current sensing circuit. I clamped the CC-65 around one of the motor leads and connected it to my scope's CH4. The onboard circuit is connected to my scope's CH1. I've attached a screenshot of the two traces, offset a bit for comparison. (CH1's cutoff on the first peak is due to saturation - the motor was drawing more current than the circuit could report. It was within the CC-65's range, though, so its output isn't truncated.)

I'd say, for the money, the CC-65 does a pretty good job of tracking what the onboard circuit reports. Would I like to have a nice Tek current probe with its standalone amplifier? Sure! But for many applications I think the CC-65 is a heck of a deal.

[Ivan7enych]

Hi,

I've got this Hantek CC-65 Current Probe.

At first test it appears, this probe outputs some parasitic oscillation (see yellow trace, blue trace is an output from UNI-T 210E current probe). On top of rectangular signal (2KHz, 200mA peak-to-peak), one can see some oscillations. Without signal the oscillations are better visible.

I've found, that inside there's a 7V stabilizer (U5B chip on top od the board, marked as PAO1), it generated some oscillations. I've added 100mkF capacitor between 7V output and ground, oscillations disappeared.

After the fix, output signal looks much better and cleaner. Probe noise is ~10mA.

[GSteuerwald]

Hi,
I own meanwhile 2 of these current clamps and confirm the oscillation on the output signal. HANTEK knew the problem and proposed to replace the capacitors C1 and C7 by 47uF/10V tantalum capacitors.
My solution: I added two low esr-elkos with 100uF/16V in parallel to the existing capacitors and the problem was solved.
Regards
GSteuerwald

Pic 1 and 2: Additional capacitors built in
Pic 3: Measured DC current: oscillation before change (green trace)
Pic 4: Measured DC current: signal after change (green trace)

[GSteuerwald]

Hi again,
one more pic showing the PCB without change and the polarity signs.
Regards
GSteuerwald

[rpress]

I bought a CC-650 with the same unstable supply.  I'm my case to solve the problem I put a 0.1uF cap in pins 1&2 of the pads for U5.

[mkee]

Just received a cc-65 as well with the same power oscillation. Smoothed that one out thanks to comments here. Would be great to be able to find out what's causing the significant and fairly quick drift. And why it needs so many attempts to get it to zero out in the first place.

[rpress]

The zero button is actually charging a cap up while it's pressed.  So try holding it down longer.

[mkee]

Of course...just realized that too...my mistake for not looking just a little closer before making that comment

[mkee]

Just thought I'd mention an observation in case someone is looking for a comparison in the future. Or if someone is trying to improve this. Seems like the drift stabilizes at around -800mA (relative to calibrated state) on high sensitivity (1mV/10mA), and -550mA on the lower sensitivity (1mV/100mA). At least noise is much improved after modification though.

[enyone]

Has anyone else noticed this behaviour of Hantek's CC-65 dc offset "walk" (see attached graph) ? There is some intervals where strange things happen and between those intervals measured values are quite static. I was wondering if it was my scope's ADC causing this but then I repeat same measurements at my multimeter and similar behaviour occured.

Test setup is one 10 watt 12 volt automotive light bulb connected to full 17Ah 12 volt gel lead acid battery (attached photo has 2 similar of them but only the one behind the the on in front is used). Plot data collected with Rigol DS1054Z which was self calibrated before measurement. Lamp was powered cold when measurement started. Hantek's clamp was "nulled" to 0 DC offset when measurement started.

[nctnico]

I see the same effect with a DC clamp from another brand. I think this has to do with the leakage of the capacitor + surrounding circuit that is charged during DC offset nulling. In other words: it is not suitable for doing long term measurements.

[bb1]

Attached is the report of testing Hantek CC-65 bought in October 2018.
Screenshots show frequency response for square and sinusoidal signals, as well as measured current amplitudes for actual currents up to 65A.
No unwanted oscillations are observed.
Saturation at 20A is reported for 1mV/10mA CC-65 setting.

[KlausF]

Does anybody has the schematics and knows where to get it?
I sought and sought but couldn´t find.

[Mechatrommer]

i just checked my topic list to find old friends but it surprised me when seeing this thread. there have been many replies throughout the years but iirc i havent get any single notification of new reply to this thread. my worst nightmare is when somebody asked me in forum and i dont see it in my "unread post" thread list i dont even know the un-oscillating capacitor hack posted 2 years ago until today i've been using this current probe in its original form happily since. and then i tried to make modification to increase bandwidth and learn its circuitry early this year, but failed since i thought, there is no room for improvement, iirc the bottleneck is the hall sensor bandwidth, you'll need to pay more for higher BW hall effect sensor. btw, i attached some of my (failed) hack attempt record if anyone interested. this is not in anyway will make you understand the circuit any better, its just showing how i tried to do it, my methodology and i think the last image is partially developed schematic from reverse engineering it i dont think i will proceed since there is not much point to it, build it? this device is cheap enough go buy it, you can spend more by getting each individual components imho. you wont get anything meaningfull but iirc this device built on several 272 opamps...

pic #1: i marked the opamp/ic orientation before desoldering them out, so i can better see traces underneath
pic #2: the pcb under the light for better visualization. opamps removed.
pic #3: the spaghetty mess try to understand it all
pic #4: the half breed schematics, i dont remember it anymore.

fwiw and cheers...

[harrimansat]

In mine, this lead of variable resistor was not soldered. One of the scales was out intermittently

[harrimansat]

The other side was not soldered on the bottom either. Once soldered it has not failed again 

[KlausF]

That is what I am interested in, in those variable resistors. What is adjusted with them ?

[electro-56]

I was unable to get the full calibration procedure out of Hantek, but when pressed they offered this:
VR1 adjusts the scaling of the 1mV/10mA range (they called it the 100mA range), and VR2 adjusts the scaling of the 1mV/100mA range (which they called the 10A range). They also suggested squeezing the clamp jaws together while pressing the "zero" button to improve the accuracy.
howie

[harrimansat]

What type of hall sensors are used? It seems a magnetoresistive bridge type no?

[Mechatrommer]

What type of hall sensors are used? It seems a magnetoresistive bridge type no?

its in the OP picture, not sure what, it has SE marking on it...

[harrimansat]

The other HP clamp that I have is colsed loop with inductor and hall. I don´t know how this clamp works. There´s more hall sensors in PCB?