#10: Kelvin versus alligators: Clips matter

[@barrykery1175]

Great video. I just received my DE-5000 today. I also did the Kelvin Clamps / Lead update. WOW ! What a great meter when used with the new leads. I make a lot of resistors for meter shunts. It was your video that showed me how important the Kelvin Clamps are. I never knew about them before. Thanks for the great video and lesson in accuracy. Barry

[@thecoinmagician]

Your lucky my DER 5000 did not calibrate properly with cheap flea bay kelvin leads..

[@francescacosentino6975]

I followed this interesting idea of ​​making a 4-wire Kelvin clamp for DE 5000 by modifying the TL-21 typically supplied with the DE 5000. I also bought the cable already made for sale on Amazon and linked in a video by the author. But I haven't had good results. As you can also read from other videos on the same topic, this cable is very cheap but it is of low quality, it is too long and often has constructive defects in the Clip attacks; defects covered by the self-shrinking sheath. I passed the calibration test both "open" and "short" but then the displayed values ​​vary a lot and the "zero" on resistance after calibration was lost immediately even if I did not turn off the DE5000. To give a quantitative value, visualizations of a few tens of random milliohms were normal. It was useless to do the calibration again because nothing changed. What was also evident was that moving the cables varied the error: as if disturbances entered: Yet I assure you that the "Guard" contact was wired as indicated with care and cleanliness. So I decided to do it all again with a better cable from a Hi-Fi shop. Basically a stereo signal cable that has a red and a white wire both individually shielded. I bought similar Kelvin Clips on Amazon like these: www.amazon.com/Alligator-Clips-Copper-Plated-Kelvin/dp/B08CBWJBXZ/ref=sr_1_17?dchild=1&keywords=clip+kelvin&qid=1615716686&sr=8-17 and I made the cable myself. I also adopted a shorter length: about 30 cm. The result was good and stable. The error after calibration fluctuates on resistance values ​​of 1-2 Milliohm and above all when moving the cables with the DE 5000 switched on, the indicated value did not change. My final consideration is: - Kelvin clips with black cable, like in this video, have better quality cable. - by reducing the length of the original cable by half, the situation improves a lot - However it is better to make the cable yourself of better quality especially in the cable (using an Hi-Fi signal cable) and using a maximum length of 30 cm. I hope I have helped someone.

[@IliyaOsnovikov]

Francesca, have you tried two-wire cables with a common shield? I've seen a comment from one blogger that separate wires in individual shields kind of defeat a purpose for 4-wire measuring method.

[@IliyaOsnovikov]

Francesca, is 30 cm overall length of the cables or the distance between alligators and TL-21 box. I've found that I would need about 4 cm within an alligator clips and about 3 cm more in a box for connections.

[@francescacosentino6975]

@@IliyaOsnovikov No , separate shield

[@IliyaOsnovikov]

@@francescacosentino6975 Thank you. I just finished that mod a couple days ago. I used 2 x 28 AWG shielded cable very similar to the original TL-21 cables and some small (5 cm - long) Chinese Kelvin alligator clips with replaceable gold plated tips that come in 3 colors: Red, Black and Gray. Following your advice I've made cables about 30 cm long. Very happy with the results. At 100 kHz after calibration I'm getting stable readings of 0.000 uH, 0.00 pF and 0.000 Ohms.

[@antoninocorallo9340]

@@IliyaOsnovikov I am very glad for you

[@jamesjefferson1059]

A well structured approach. thank you for committing the time and effort to this question.

[@TheRadiogeek]

I have the DE 5000 as well. I like this meter a lot but I haven't made a set of kelvin clips yet. Thanks for the video. I think you're doing a nice job on your channel.

[@radiophysicsandelectronics6923]

Thank you!

[@Snowsea-gs4wu]

AWESOME channel, thanks for the video! Sad to notice that you stopped making videos around five years ago… in other circumstances I would have said keep up the great work! Thanks!

[@spelunkerd]

I was a little surprised at how carefully done and reproducible your little experiment is. On the surface I would have thought the contact area between the teeth and the wire is a bottleneck spot of low cross sectional area, presumably accounted for when zeroing the device electronically. The whole topic makes me wonder what errors might creep into measurements regarding capacitance and inductance. With variance in current and voltage and even frequency, I wonder how accurate the zero calibration can be.

[@mikes1031]

Great video with way more tech info than I could understand, but you sure made the point that the clips matter a lot. Thank you for the important info.

[@dennisschultz1175]

How do the alligator clips versus the kelvin clips compare when it comes to low inductances?

[@IliyaOsnovikov]

Radio Physics and Electronics, Thank you for the interesting video. I am also planning to replace original TL-21 clips for the Kelvin clips with longer cables. Francesca Cosentino in a post below recommended using somewhat shorter cables (up to 30 cm). And the original TL-21 cables are just a few centimeters long. What would be the optimal/most practical length for those cables if I use 28AWG twisted pair shielded cable with PVC insulation (about the same as the factory cables)? Would it be benefical to use a cable with better insulation like PE, PP or FEP?

[@2L40K]

It's really interesting.👍 But I also wonder what it will be for AC measurements of capacitors and inductors.

[@TRXLab]

Nice video, great work! Thanks for linking my video. Just found you channel and like it!

[@radiophysicsandelectronics6923]

Thanks for your comment, I'm a fan of your channel!

[@krunty]

Does the DE-5000 utilize the Kelvin connection while measuring other impedances or just resistance? Does it make a difference while making an ESR measurement?

[@behemothinferno]

These Kelvin Clips you are using seem to be connected to one of the two parts of the "jaw". Each wire should be soldered to the individual gold plated copper connectors and should only be shorting out when the two halves of the jaws are in contact with each other. Just making sure this is the case.

[@kilgoretrout5456]

They are soldered to both jaws. They only run up one side though. One wire keeps going to the other jaw.

[@jeanpierredaviau7478]

Would 50 ohms Kelvin leads would do?

[@xamosinsertlastnamehere5196]

Thanks for the video and demonstrating that this can be an issue. However, while the added stabilty this modification yields is nice, this meter specs at 1% +3 digits in the DCR range. So it's a bit pointless to use it for milliohm measurements to begin with.

[@radiophysicsandelectronics6923]

Indeed, and that is the reason I picked that range: the meter should not be precise in that region. I wouldn't depend on milliohm measurements with this meter without independent measurements or reality-check calculations to corroborate, as done in this video, but I thought it was interesting that the clips made readings less variable. Thanks for your comment.

[@radu3g]

My DE-5000 came with a second adapter, TL-22, which looks almost like Kelvin leads. The only difference is that the wires in each pair are connected together about 30 millimeters away from the measuring tips. The tips are looking like they are gold plated, so measurements should be close. If I get myself the real Kelvin probe I will came back with numbers.

[@AlexandreJasmin]

The TL-22 are sold as SMD tweezers, not regular test clips. They're spring loaded so you have to squeeze them closed. goo.gl/w1B1mZ

[@JDW-]

@ITTSB Blog Europe, I read your review from 2012. Very informative, thank you. But would you say the DE-5000 is still one of the best LCR hand-held meters now in 2018?

[@sharymens8187]

how did they compare?

[@oksanaskotarenko3054]

Может для начала стоило откалибровать, прежде чем измерять такие малые сопротивления

[@3madeamps]

show me how to Measur some inductance coils ..

[@DachaLife]

interesting to a point but i was falling asleep lol