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 Subject :ac/dc current probe with built-in oscilloscope display.. 2014-01-25 09:10:56 
vile_fly
Joined: 2014-01-25 14:16:01
Posts: 2
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The automotive diagnostic world needs a DC current probe with the oscilloscope display built-in. 

http://www.ebay.com/itm/CP-06-AC-DC-Current-Probe-/121242016993

Like this, but with a display and one zener protected AUX input for the other channel.  The xprotolab seems more than adequate for the task.  The display configuration may be an issue. 

The range needs to be 1mA to 20A, selectable ranges.  Accuracy is not so important as being able to see the shape of the waveform clearly.  The shape of the waveform is much more important in the automotive field.

I am slowly working on this, but know I am in over my head.

However, I just found this hall effect current sensor IC.

http://www.melexis.com/Hall-Effect-Sensor-ICs/Special-Purpose-Hall-ICs/MLX91206-755.aspx

From the looks of this, a solid plastic probe with this sensor in the tip might do the trick without having a mechanical clamp around the wire.  Maybe.  Check the datasheet.

 

 

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 Subject :Re:ac/dc current probe with built-in oscilloscope display.. 2014-03-06 08:55:36 
7tronics
Joined: 2014-02-26 23:15:42
Posts: 11
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I have a Tektronix AC clamp-on probe (3A max) that I use with the Xminilab Portable, and a tried and true old clamp-on 400A probe Tenma probe that I use with a variety of DMMs.

I hear you that an equivalent to the Sinometer UT204 ( http://www.amazon.com/UT204-True-RMS-Auto-ranging-Clamp-Meter/dp/B005G4VKFY/ref=sr_1_1?ie=UTF8&qid=1394135442&sr=8-1&keywords=sinometer+ut204 ) with a built-in scope interface should be a hit for the electric vehicle (EV) crowd, eh!

We are thinking about getting a B&K Precision CP3 (http://www.amazon.com/Precision-CP-Clamp-Meter-Accessory/dp/B005T8BBCY/ref=sr_1_1?ie=UTF8&qid=1394135342&sr=8-1&keywords=B%26K+CP3 ) which looks like a decent probe to marry to an Xminilab or Xprotolab Portable and attached laptop or tablet or use with the bench scope!

[Edit] we realize that there will likely be phase delays, so showing current vs voltage events with a probe like this meant for use with a DMM may be less than optimal. It will allow visualization of current AND voltage waveforms though the current waveform may be timeshifted and require some calibration of the current waveform timebase.

[Edit2] Your range request is interesting, 1mA to 20A. Typically to get accuracy in the mA range, one needs a very different size probe than for a few amps and up. So the Tektronix probe (and there is a real expensive AC/DC version) has a tiny clamp and a lot tighter tolerances compared to the probes for higher current and larger wire. Separate post I found a Fluke probe with 2A and 200A ranges that is often available for US$20 + S/H.

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M R Smith, 7tronics, Central NC
 Subject :Re:ac/dc current probe with built-in oscilloscope display.. 2014-03-06 10:09:11 
7tronics
Joined: 2014-02-26 23:15:42
Posts: 11
Location

 On perusing eBay, perhaps looking for a Fluke Y8100 to go with an Xscopes portable is a really good combination!

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M R Smith, 7tronics, Central NC
 Subject :Re:ac/dc current probe with built-in oscilloscope display.. 2014-03-13 14:13:14 
vile_fly
Joined: 2014-01-25 14:16:01
Posts: 2
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We use the tektronics amp clamp quite regularly, but the smaller version runs 10 mA to 40A, and I have two of each. This is the low amps probe we most commonly use. http://www.aeswave.com/Current-Probe-Low-range-Generic-brand-p8486.html
I prefer a range of 1mA to 20A (ac/dc) in an ideal world, but I will use what I can get a hold of.
My CAD drafting skills are lacking enough to stop me from 3d printing a new case for this unit........for now. I barely made a housing for the xscope that fits as it is. I need to have the case 3d scanned in for me do the job right. The add-on case would be the most effective way to improve an existing tool without infringing on patent rights.

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 Subject :Re:ac/dc current probe with built-in oscilloscope display.. 2014-03-13 15:33:55 
7tronics
Joined: 2014-02-26 23:15:42
Posts: 11
Location
We just acquired a light blue version of same probe but with BNC connectors to go with our Tektronix AC only probes. This generic probe is not up to Tektronix quality, but for almost 1/10th the price, very acceptable for use on ebikes and audio system diagnostic work.

For use in the rain or really damp environments, we are experimenting with the type of "dry bags" often used for protecting mobile phones on camping and canoing trips. They allow fine cables to go through a doubled over section of the bag but don't squish the cables. As long as cables in and out of the Xscopes Portables are about the thickness of mini-bud headsets, seems to provide good protection. Front panel push button controls are accessible, but the switch controls aren't. If they were all push buttons, this type of dry bag would work very well.

We have both an Xminilab and Xprotolab Portable and the tripod mount cases from Gabotronix. The Xprotolab Portable with two short BNC to 1/4" mono phone plug and dual BNC probes plus a 1/4" mono phone connection for AWG + micro USB all fit a bit better on the Xprotolab Portable + tripod mount, especially with the display upside down while using the tablet or laptop as the display.
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M R Smith, 7tronics, Central NC
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