Milliamp clamp shootout

Hans Diagnostician Salt Lake City, Utah Posted   Latest  

I just got my K100 Microprobe amp clamp and wanted to see what it could do. Subject is the N80 EVAP purge valve on a 2003 VW Eurovan (what was running in my bay). I clamped all three around the same wire so I could compare them. I'm using a Pico TA018 20/60 amp clamp on the 20 amp mode, a K100 Microprobe, and a TA189 30 amp clamp.

When I looked at the results, it's clear that the k100 has a much cleaner trace than the other two. These are unfiltered as well. I also noticed the current numbers were different between them. The TA018 read the highest at around 503 mA and the K100 and TA189 both read around 478 mA.

It's interesting to see the saw tooth pattern on the TA018 that isn't present in the other clamps. I don't think it was interference from anything because even when I moved the clamp around it didn't change. It's also interesting to see the difference in the trace amplitude? unfiltered in the TA189. It has a very good accuracy rating, but without being filtered, you might not get that exact current.

Another thing I've noticed is the TA189 will drift if it's not fully warmed up. It seems like it takes around 20 minutes or so for it to get to operating temp. It WILL drift up in amperage pretty significantly (in milliamp terms) when cold. I did not experience this with the TA018 or the K100 during this test.

The TA018 jaw size is good, measured at 8mm. The TA189 is giant, measured at 30mm and is great for a quick parasitic draw test. You can clamp around the battery cable easy. The K100 is very small, measured at 4mm. This is the larger version of the Microprobe with a total amp rating of 4.5. The K110 only measures to 450 mA.

So it looks like they all have their strengths and weaknesses. The TA018 is fairly inexpensive compared to the other two, and is included in many of the Pico kits. I'm definitely not sad I spent the money on the other two clamps because they have their place in my tool box. I am glad to know the resolution of the K100 is so good though, if it comes to splitting amps somewhere, I know that will be my go-to.

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Mario Diagnostician
Weston, Florida
Mario
 

Great shootout hans. Thanks for sharing. Very useful to see the side by side comparisons.

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Richard Instructor
Palmetto, Florida
Richard
 

So the question remains for me....is the micro amp clamp worth the added expense? I know you didn’t pay full price for it but what test can I do with it that my regular low amp probe can’t do?

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Thomas Diagnostician
Saint Petersburg, Florida
Thomas
 

I was thinking newer wheel speed sensors to start with, perhaps.

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Chris Technical Support Specialist
Commack, New York
Chris
 

If I remember correctly, Ford active wheel speed sensors switch from 7 - 14 mA

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Cliff Diagnostician
Santa Maria, California
Cliff
   

Richard I see it working similarly to a torque wrench... Meaning use the one that is closest to the actual amperage used for the circuit. I have been on the fence about ordering a micro amp clamp for a few years, as time progresses the "pioneers" have thought of more ways to use them. Brandon Steckler used it in a very inventive way on his case study with the Buick I believe it was. Just my humble slightly drunken thoughts.

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Richard Instructor
Palmetto, Florida
Richard
 

Yea, I understand it has its uses but I just didn’t see the worthwhile return on investment. the last time I looked at prices it was expensive and I have yet to see enough tests that warrant Me buying one yet. 

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Eric Owner/Technician
Edgerton, Wisconsin
Eric
 

I've had one for a while and agree it's like a torque wrench proper tool for the job at hand. I wouldn't want to work without it now. It gives a cleaner signal at the lower current draws than my higher amp clamp.

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Brin Diagnostician
Melbourne, Florida
Brin
 

Hans,

Thank you for your work. I've been considering the K100 or the K110 for a little while now but I would be curious to learn where others are using these probes for. I would think that these micro amp probes would be great for sensor circuit and network diagnostics. It's probably about time that I did look at picking one up.

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Darren Mechanic
West Allis, Wisconsin
Darren
 

K100 great for can network troubleshooting.

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Chris Diagnostician
Commack, New York
Chris
 

I would like to see that in action. Do you have any captures of it being used this way?

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Hans Diagnostician
Salt Lake City, Utah
Hans
 

I"m guessing if you have a comb or easy connector to get to, you can just clamp each one to see if it has traffic? A bit faster than backprobing or jumping each connector.

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Richard Instructor
Palmetto, Florida
Richard
 

I would love to see that, I thought the frequency response was way too slow to catch anything useful for diag. I’ve seen other people try to use it and wasn’t impressed with the results. 

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Hans Diagnostician
Salt Lake City, Utah
Hans
 

Part 2 of this test was on my Westfalia I just picked up that is wired for a coach battery that feeds the radio and the cabin lights. It was a very easy wire to reach, and had enough room for all my clamps. Nothing was on except the radio memory.

I started off with all of the settings at 500mA and unfiltered.

Right away the K100 looks like a cleaner capture than the rest. Next I zoomed in and was able to adjust my horizontal cursor a little better.

500mA is the lowest standard setting in the presets for the amp clamps, but when I setup the new preset for the K100, I went down to 50mA. This capture is using that 50mA setting and unzoomed.

You can see the difference here, and once all the channels are filtered, you can really see a difference.

I need to do this test again and modify the TA189 preset to go lower to 100mA or so, because that clamp should have the resolution to have been closer than this test says. I was a little disappointed in it's performance at this low current. But like mentioned above, different torque wrenches for different fasteners, and so different amp clamps are needed for a broad range of current measuring.

I think the most surprising result is how close the TA… clamp was. The resolution at that low current is terrible, but maybe I just got lucky this time and it was in the ballpark! I might also try a battery change in my TA018, or try my other clamp and see if the sawtooth pattern is still there in that clamp. In all, I'm happy with my K100 and hope to find many uses for it in the future!

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