Absolute Best MultiMeter Test Leads - Very Low Resistance? - Page 1
Forum section: electronics / testgear

author: nytefog
author_rank: Newbie
timestamp: January 02, 2024, 11:41:06 pm
content: Hello,I’m in search of the absolute best multimeter test lead available that have the lowest possible measurable resistance available.The fluke TL175 test leads I normally use for everyday testing always seem to have 0.5 ohm resistance reading. I’ve tired cleaning the test leads and meter connection ports but it makes little difference. I have even tested a set of brand new fluke TL175 lead and the have about the same resistance. I tested them both on a Fluke 87v and 289.I recently bought some Probe Master 8100 test lead which definitely have a much lower resistance, which I can’t remember off the top of my head now, and I am happy I got them but hoping there might be test leads that are a step above Probe masters or multiple steps above them!Does anyone happen to know of any better meter test leads to that have almost no measurable resistance? I know they will always have some resistance of course. I know this is probably not a common question people ask. I know I should have a 4-wire kelvin milliohm meter for measuring very low resistance reading, but i really can’t justify the cost of such a meter at this time. I would really love to get a Gossen Metrawatt Metrahit IM Tech BT multimeter (M272S) but that is definitely out of the question as of this time.I love to hear any suggestions. I’m sure others are much more knowledgeable about this subject than I am.I appreciate any and all feedback!

author: Whales
author_rank: Super Contributor
timestamp: January 02, 2024, 11:48:55 pm
content: Is the 0.5R only from the leads or noticeably from the multimeter itself (eg input fuse)? It might be worth checking with a big metal shunt across the input jacks.

author: bdunham7
author_rank: Super Contributor
timestamp: January 02, 2024, 11:50:48 pm
content: Quote from: nytefog on January 02, 2024, 11:41:06 pmIf you have the 8000-series with the fixed probe tips (and threads) then the body of those tips is stainless steel which has higher resistance--although the gold plating helps. If you have the 8150 retractable "pogo-pin" style, then you probably have one of the lowest resistance probes that I know of, with the drawback that the resistance varies a bit. There's only so much you can do with a 2 wire system. There are almost-4-wire systems that have 4 banana plugs or the equivalent, dual conductors going to each tip and then a low-resistance tip. I tried making some using ProbeMaster 8000-series parts, but the resistance of the tip body was enough to make it not as good as it needed to be. What multimeter or ohmmeter are you using?

author: tggzzz
author_rank: Super Contributor
timestamp: January 02, 2024, 11:58:39 pm
content: So you think low resistance leads will solve your problem, but you haven't explicitly stated the problem and your objectives (including numbers, not adjectives). For an example of how that can be important, seehttps://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/Errors in measuring resistors below, say, 10ohms can have many sources of error, including variable contact resistance, I2R heating causing resistance changes, thermoelectric (Seebeck) voltages.If none of those are significant, you could do a differential resistance measurement, subtracting out the lead resistance. Alternatively, use a Wheatstone bridge.

author: The Electrician
author_rank: Frequent Contributor
timestamp: January 03, 2024, 01:22:40 am
content: Just short the probe tips together while in ohms mode. Subtract that value from any measurements you make of very low resistance components.Some multimeters have the ability to automatically subtract the lead resistance. My Fluke 187 has a button labeled "REL" (relative). I just short the probe tips, press "REL", and the display then shows "0.000". Measurements I then make will have the lead resistance subtracted from the measurement.

author: tooki
author_rank: Super Contributor
timestamp: January 03, 2024, 02:20:51 pm
content: Quote from: nytefog on January 02, 2024, 11:41:06 pmWhat do you expect to gain from further improving the leads? For voltage measurements it doesn’t matter. For very low resistance measurements you need 4-wire measurement anyway (and then the lead resistance doesn’t matter). It doesn’t really matter for current. So…?

author: alm
author_rank: Super Contributor
timestamp: January 03, 2024, 02:32:44 pm
content: I agree with tooki.f you want to measure low resistance, this is easy to improvise. Use a bench power supply to source a constant current, like 100 mA. Set the voltage limit low enough so it won't cause excessive dissipation in the resistor. Run this current through the resistor, and with different leads connect a DMM across the resistor and measure the voltage. Use either the power supply's built-in meter or a second DMM to measure current. Then calculate resistance using Ohm's law. This pretty close to what an ohmmeter is doing in four wire mode, except less convenient.

author: bdunham7
author_rank: Super Contributor
timestamp: January 03, 2024, 04:32:15 pm
content: Quote from: tooki on January 03, 2024, 02:20:51 pmSometimes you just want reasonably decent and reliable low resistance readings but don't need many decimal places. Kelvin measurements can be inconvenient. The key really is reliable, consistent overall test lead circuit resistance, including the contact resistance. Obviously low is also better, but consistency comes first. There can be a huge difference between ordinary test leads in this regard even among versions that work just fine in other situations. Some of the nickel-plated (or whatever they are) Fluke leads are terrible for this, even though they work very well in other situations.OTOH, I have ProbeMaster 8150 leads with the CuBe "pogo-pin" ends that I use with my old 4.5 digit Nixie-tube DMM and even though its lowest resistance range is 1k, it fairly reliably reads out low resistances to within 1 count (0.1R). So IMO pursuing better two-lead solutions is definitely worth it--to a point. The ultimate quasi-two-lead solution is Fluke's 2X4W system, but there are only three meters that use that and two are discontinued.

author: tooki
author_rank: Super Contributor
timestamp: January 03, 2024, 05:37:40 pm
content: Quote from: bdunham7 on January 03, 2024, 04:32:15 pmYeah I understand all that, but I asked what they expect to gain byfurtherimproving the leads, i.e. beyond the already-superb Probe Master 8100 they already have?

author: bdunham7
author_rank: Super Contributor
timestamp: January 03, 2024, 10:43:31 pm
content: Quote from: tooki on January 03, 2024, 05:37:40 pmI don't see an 8100 model, so I wanted to be clear that the pogo pin style was what he has. If not, there is clear improvement to be had by going pogo.As for further improvement, as I mentioned sometimes Kelvin sensing is impractical and the Fluke 2X4W system gives you the convenience of normal probes with much better performance, perhaps 100X better than a typical 2W setup. You can also get a probe set from Pomona the does something similar with almost any 4W-ohms meter. I tried making my own, but was unable to source a decent tip end and the ProbeMaster SS tips don't work well enough. If the OP has a compelling need to do low-resistance measurements with probes, than this is the way to go.

author: mqsaharan
author_rank: Regular Contributor
timestamp: January 04, 2024, 07:38:32 am
content: Hi nytefog,I haven't read the whole thread, somebody may have mentioned it already; For lowest resistance and worst probe end, because it is blunt, get Uni Trend's UT-L21 probes. They are, of course cheap, have some type of PVC insulation. They are included in UT195DS multimeter. HKJ (also a memeber here) tested their resistance as 14mOhm per lead with 88cm lead length (https://lygte-info.dk/review/DMMUNI-T%20UT195DS%20UK.html).My guess is any multimeter probe that is designed for high current will have lower resistance than the normally available 10A probes.

author: tooki
author_rank: Super Contributor
timestamp: January 04, 2024, 12:01:35 pm
content: Quote from: bdunham7 on January 03, 2024, 10:43:31 pmOops, you’re right of course. It’s been a while since I ordered anything from Probe Master so I just wrote what OP wrote, but yeah, it’s either 8000-series rigid-tip or 8150-series pogo-pin.Quote from: bdunham7 on January 03, 2024, 10:43:31 pmBut that won’t help them, they don’t even have a 4-wire multimeter.I am still unconvinced that trying to find “better” probes than Probe Master (regardless of whether it’s 8000 or 8150), if such a thing even exists, will make any meaningful difference in the 2-wire measurements they are doing. My whole point was that if you want to do better than this, they need to do 4-wire measurement, which is itself inherently less fussy about the test leads.

author: Fungus
author_rank: Super Contributor
timestamp: January 04, 2024, 01:47:36 pm
content: Change your technique. No leads are perfect.Resistance? Use four wires.High current? Get a clamp.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 04, 2024, 01:57:18 pm
content: Silicone test leads BL21S2-T4SC Brymen

author: bdunham7
author_rank: Super Contributor
timestamp: January 04, 2024, 02:58:56 pm
content: Quote from: Fungus on January 04, 2024, 01:47:36 pmSo you have something with two power supplies on board, 3.3V and 1.8V. They each have an 0805 current sense resistor, one 0R005 the other 0R010. You need to verify that the correct one is installed in each location and that the resistors are reasonably close to nominal value, as in making sure the wrong part hasn't been installed. And you have a large stack of them that you need to check right away to determine which, if any need rework. Out of all the methods discussed so far, which one would you like to use?

author: tooki
author_rank: Super Contributor
timestamp: January 04, 2024, 03:05:26 pm
content: Quote from: bdunham7 on January 04, 2024, 02:58:56 pmThe OP hasn’t given us any indication that their application resembles this example in any way, but weknowit’s not a use case for the multimeters they own, since they don’t have anywhere near that resolution.

author: bdunham7
author_rank: Super Contributor
timestamp: January 04, 2024, 03:42:59 pm
content: Quote from: tooki on January 04, 2024, 03:05:26 pmI don't know the OP's precise use case and he asked for "any suggestions". His Fluke 289 has a 50.000R LO-Ohms (also known as SLO-Ohms) that has the exact same 1mR resolution of the 8808A I pictured earlier. That 50R range is very slow to settle and pretty fussy, so it is hard to get the same 2-3 count stability and repeatability as with the earlier example. Still, one might imagine that it is possible and become quite frustrated or hope that better test leads would help get that last digit to settle down.Just to provide an idea of reasonable expectations here, the specified tolerances at 10R come out to 11 counts for the 8808A, 22 countsafter using REL to compensate for offsetsfor the 289. Both meters easily exceed expectations with reasonable technique.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 04, 2024, 07:16:13 pm
content: Quote from: alm on January 03, 2024, 02:32:44 pmJust some notes:1) The leads used for current are the "DUT" leads.2) The test is only as good as the accuracy in amps and volts readings. 2 of 3 variables in E/IR need to have high accuracy to get high accuracy in the 3rd derived value. Kelvin types are only as good as their accuracy in measuring the amps and the volts.3) Using the extra psu and meter(s) will likely introduce more error than just the leads themselves?4) 2 lead or Kelvin, the measurements are only as good as the tolerance stated, which can change depending on the range setting used.Meters that can inline a known precision resistor internally when going into "cal" mode with shorted leads, means the meter can use any leads, you just re-cal each set of leads.I use a method for some machine work stuff. I obtain a "calibrated" and "accurate" item from which all my crap uses as a reference. Same can be done for elecrical stuff too. Obtain a precision laser trimmed "certified" resistor (usually in an IC package) and use that as the known. It could be a 1k that is certified as 1.0000213 k ohm. That's your reference item. Do the same for a cap, inductor, and some voltage reference IC. They become your references for all your measuring tools. Calibrate your stuff (if possible) to those items, or if you can't tweak the meters then at least you have a known offset you can carry along. Obviously there could be some non-linear areas of the meter, so that's why it's good for tools to have calibration maps, which I don't think any handheld has.

author: shapirus
author_rank: Super Contributor
timestamp: January 04, 2024, 07:33:06 pm
content: Quote from: nytefog on January 02, 2024, 11:41:06 pmIt's either your measurement method is incorrect, or these leads are utter garbage (or are damaged). There is no way decent leads can have such high resistance.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 04, 2024, 07:46:57 pm
content: I recently got 2 set of test leads from Probe Master but they aren't for the Fluke. They are both for the Simpson meters. One is pin and the other is reverse banana. The Simpson being analog so the test lead small resistance is not noticeable.

author: Fungus
author_rank: Super Contributor
timestamp: January 04, 2024, 08:05:48 pm
content: OP hasn't actually said what they're achieve yet, so...

author: tggzzz
author_rank: Super Contributor
timestamp: January 04, 2024, 08:15:41 pm
content: Quote from: Fungus on January 04, 2024, 08:05:48 pm... despite being asked on at least one occasion.

author: J-R
author_rank: Super Contributor
timestamp: January 04, 2024, 08:52:45 pm
content: With regard to the question about measuring the current sense resistors, I prefer to REL out the test leads/probes when they are connected to the same side of the DUT. Then move one probe to the DUT's other terminal to make the actual measurement. This maintains consistency with regard to how the probe is making contact with the DUT, such as the side of the probe, or the pointed tip, for example.In addition, if this measurement is super-critical, follow the above procedure a few times in order to gather consistency info. You may need to adjust your method.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 02:35:14 pm
content: Quote from: bdunham7 on January 03, 2024, 10:43:31 pmYour 2-wire 4-wire test is interesting. Are your 2-leads compensated for in any way? I ask because if they are not then we know something is perhaps off with your tests? Each test wire is expected to have more than 1.46mOhm per foot.I did a little data searching, apply some physics. The best economical wire is likely gonna be silver plated copper wire. In kinda ideal circumstances such wire that is 12awg will give us approx 1.46mOhm per 30.48cm (1 foot). That's just for wire. Need to also account for junction points of different metals.If your test leads are 1ft each and 12awg, we should expect to see your meter pick up a diff of ~3mOhm between 2-wire and the 4-wire test.Your meter seems to only show a diff less than 1mOhm, displays closest 1mOhm (assumed to be from rounding), etc. Each probe wire is expected to be more than 0.5m ohm.Another thing to note, 10.000 ohms vs 9.999 ohms can actually be way less than 1m Ohm depending of how the unit rounds off in order to paint the digital display.Eg; if it rounds up at the 0.5 mark and down when under 0.5, a diff of just 0.0001 ohm (0.1m ohm) could mean a display diff of 10.000 vs 9.999 (1mOhm). That's a 10x differential between measured and displayed.What if you swap out that 10Ohm DUT with the kelvin current wires to see what the wires ohm in at?

author: Haenk
author_rank: Super Contributor
timestamp: January 05, 2024, 02:56:29 pm
content: Quote from: BILLPOD on January 04, 2024, 01:57:18 pmI have the ProbeMaster (both springy and normal) and Brymen. The ProbeMasters are certainly nicer, but the Brymen are not too bad either (esp. considering the price) - so the Brymen probes stay with the Brymen meter.

author: 2N3055
author_rank: Super Contributor
timestamp: January 05, 2024, 03:02:50 pm
content: Quote from: Randy222 on January 05, 2024, 02:35:14 pmThose are special Fluke TL2X4W-PTII 2x4W test probes that are also 4W in compact form. It is not 2W setup

author: tooki
author_rank: Super Contributor
timestamp: January 05, 2024, 03:06:05 pm
content: Quote from: Randy222 on January 05, 2024, 02:35:14 pmYou missed the point — those aren’t standard two-wire probes. They’re special 4-wire kelvin probes that have kelvin connections right to the points, and then special custom 2-conductor banana plugs, so that that dual plug is actually 4 wires.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 03:08:50 pm
content: Quote from: 2N3055 on January 05, 2024, 03:02:50 pmAre they just ungrounded-shielded 1-wire per probe?That 1st pic shows just two single probes.

author: 2N3055
author_rank: Super Contributor
timestamp: January 05, 2024, 03:12:31 pm
content: Quote from: Randy222 on January 05, 2024, 03:08:50 pmJust google Fluke TL2X4W-PTIIThese are special 4W probes that work only with certain Fluke DMM

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 05, 2024, 03:14:59 pm
content: Quote from: Haenk on January 05, 2024, 02:56:29 pmI have several sets of ProbeMasters (also both normal and springy) as well as a few extra sets of Brymen leads besides those that came with my Brymen meters. I love the PMs but they're a bit bulky to keep with smaller handheld DMMs so I keep them at my bench, and use the Brymen leads for portable use. Especially as replacements to the now-crappy TL75 leads that Fluke ships now. The Brymen leads are excellent, and an outstanding value at ~$10 a set.I also have several sets of cheap Chinese leads that cost <$5 that are surprisingly good. Silicone (or at least very soft PVC, I haven't tried the melt test) wires and sharp gold-colored (plated? not sure) probes.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 03:16:16 pm
content: Quote from: tooki on January 05, 2024, 03:06:05 pmAhhh, so the current wire and the Vsense wires terminate somewhere in the probe downstream from probe tip? Doesn't that leave a little ohms between current path and Vsense points?With the std 2-clamp 4-wire you are clamping current and Vsense at the same points.

author: 2N3055
author_rank: Super Contributor
timestamp: January 05, 2024, 03:19:22 pm
content: Quote from: Randy222 on January 05, 2024, 03:16:16 pmIt does, but at very low resistance value that is below/ almost below what those meters can measure anyways...Not perfect but superior to 2W setup but still simple to use...

author: tooki
author_rank: Super Contributor
timestamp: January 05, 2024, 03:21:14 pm
content: Quote from: Randy222 on January 05, 2024, 03:16:16 pmCorrect.Quote from: Randy222 on January 05, 2024, 03:16:16 pmYep, we know that.

author: bdunham7
author_rank: Super Contributor
timestamp: January 05, 2024, 03:28:04 pm
content: Quote from: Randy222 on January 05, 2024, 03:16:16 pmThe 'wires' are coaxial cables and the left set of input jacks on the meter are something they call "Split Jack" connectors. It has what looks like a banana jack but there are two separate sides. If you plug a standard banana plug into it, it simply bridges the two sides. In the picture I've plugged in a set of the 2X4W test leads that have matching split plugs internally. Yes, the both sides of the coax are soldered to the probe tips so you have a bit of resistance left at that end, but they use gold-plated CuBe for those tips and the residual resistance is less than one milliohm per tip measured at the sides, a tiny bit more if you are using the sharp point.The whole setup has the advantage that you can use the meter normally on other ranges without changing the probes, in addition to getting good low resitance readings without using Kelvin clamps.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 03:28:43 pm
content: Quote from: 2N3055 on January 05, 2024, 03:12:31 pmI see them. (https://www.fluke.com/en-us/product/accessories/test-leads/tl2x4w-ptii/ds)Those ports must have dual contact in each port? (as just read in the reply behind this one).Given there's still a small current path outside of the Vsense on DUT side, let's say just 0.75" between tip and junction point in probe case, 0.75" of std copper wire of 18awg (probe tip dia), is gonna be around 0.406m-ohm each, x2 for 0.812m-ohm, which is enough to make a meter that reads to nearest 1m-ohm display non-accurate reading (assume using a 0.5 rounding scheme).The 4-wire (two jack) setup that has just two probe tips, needs to have the tips fat and very short so that the ohms there adds into any rounding the meter will use, of which all efforts simply bring you back towards the 4W 4-probe configuration. Eg; actual is 1.0034 ohm, ideal is meter shows 1.003. Add in just 0.1m-ohm from probe tips, meter reads 1.0035 and then rounds up for display of 1.004. Yikes, the probes (super low additional ohms) makes the meter tell you the measured is 0.6m-ohm more than actual, vs 1.003 which is 0.4m-ohm below actual, yet from just the display diffs you see it as a 1m-ohm diff ! This appears to be what the pics have shown?So I guess, why use a 4W 2-probe if the goal of any 4W is to remove any probe ohms from the readings? With the 1m-ohm resolution meter, the diplayed diff from error is near 1m-ohm, whereas the 4W 4-probe the displayed diff is from device resolution rounding.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 03:57:15 pm
content: Quote from: Veteran68 on January 05, 2024, 03:14:59 pmAny test leads for ohms, at least ones anyone can afford to buy, will be no better than silver plated copper wire that is soldered to termination using high silver solder.For perhaps bench tests, practical use limitations seems to be near 1ft 12awg.A meter that is tuned for best possible performance perhaps does not have panel jacks, but rather the wire is soldered directly to PCB to remove insertion/contact losses. 0.1m-ohm here, 0.1m-ohm there, it all adds up.

author: tooki
author_rank: Super Contributor
timestamp: January 05, 2024, 04:31:07 pm
content: Quote from: Randy222 on January 05, 2024, 03:28:43 pmThe probe tips are 2mm diameter, which is very close to 12AWG, not 18AWG.12AWG copper has a resistance of approximately 0.00521 ohms per meter.0.75” = 19.05mm = 0.01905mSo the resistance of one probe tip is 0.00521 x 0.01905 = 0.0000992505 ohms. That’s about 100μOhm, significantly less than the 406μOhm you calculated (which would be correct for 18AWG).The 200μOhm probe resistance is an order of magnitude smaller than the accuracy spec of the best multimeter that can use these probes (8846A, 1.3mOhm maximum error for tightest spec), and two orders of magnitude smaller than the accuracy spec of the meter shown in the pictures (8m08A, 10mOhm maximum error for tightest spec). In both cases, calculated using the actual resistance and applicable range.So I really don’t think this is a real problem.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 04:52:09 pm
content: Quote from: tooki on January 05, 2024, 04:31:07 pmJust checking my math. 0.75" 12AWG copper is approx 0.09674 m-ohmx2 = 0.19348 m-ohmSo yeah, that's approx 5x below resolution of the display. However, the +0.2 m-ohm can still help trip rounding, which can look like a full 1 m-ohm diff on display.Silver plated copper may improve things, but obviously oxidation plays a role. But since they can stick to each other I wonder if you can find copper plated silver to get between copper and silver-plated-copper.

author: bdunham7
author_rank: Super Contributor
timestamp: January 05, 2024, 05:52:05 pm
content: Quote from: tooki on January 05, 2024, 04:31:07 pmQuote from: Randy222 on January 05, 2024, 04:52:09 pmThe 8808A 1-year spec would be 11 counts or 11mR, the 8846A would be 400 counts or 4.00mR (it has a 10R range in addition to the additional digit, along with a 5mA test current). So while the effect of the probe tip resistance might be observable on the 8846A, it is pretty small compared to any reasonable expectations for the 8808A, which will typically wander around a few counts of 1mR each. With the 8846A using the ZERO (aka REL) function seems to be an improvement for looking at relative or near-zero resistances, but the overall effect is probably not much more than the best-case unexpanded uncertainty of the meter itself. Also, thermal and contact voltages can cause variances greater than 1mR, even with Kelvin clips. Gold-plated copper is the way to go IMO.Here's a demonstration. If I were trying to impress you with the 2X4W system, I'd just show the first photo! But the reality is that microohms are hard to measure with small DC test currents.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 05, 2024, 05:59:10 pm
content: The resistance if the probe is not the main quality point. The more tricky parts are contact resistance (as this is not that well reproducible) and the thermal EMF - so how much extra voltage is seen if one had touched the probes and made them warm a little. With poor probes one may get to the 100µV range this way. Part of the effect may also come from inside the meters, so it is not such an easy part to test.Another point can be the quality of the isolation, when measuring high resistance (e.g. 100 M range). This would be less with a handheld meter, but could be a thing with a good bench meter.

author: bdunham7
author_rank: Super Contributor
timestamp: January 05, 2024, 06:23:58 pm
content: Quote from: Kleinstein on January 05, 2024, 05:59:10 pmYes, it's worth pointing out that the .00052 ohms of the probe tips as shown in the above photo represents 2.6 microvolts at a 5mA test current.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 05, 2024, 08:40:06 pm
content: On that 8846, if you remove any REL setting and clamp the probes together at midpoint, what reading do you get?

author: bdunham7
author_rank: Super Contributor
timestamp: January 05, 2024, 08:54:25 pm
content: Quote from: Randy222 on January 05, 2024, 08:40:06 pmBetween 1 and 3 milliohms, with a bit of variability depending on exactly how you hold them.

author: evmillan
author_rank: Newbie
timestamp: January 08, 2024, 01:17:32 pm
content: In case you want to measure very low resistances, for less than the price of two pairs of Fluke test leads you can buy the PeakTech 2705 Milliohmmeter.https://www.peaktech.de/uk/PeakTech-P-2705-Digital-milliohmmeter-4-000-counts-400-mO-4-40-O/P-2705It comes with 4-pin Kelvin test leads

author: Randy222
author_rank: Frequent Contributor
timestamp: January 08, 2024, 01:53:38 pm
content: Quote from: evmillan on January 08, 2024, 01:17:32 pmBe nice to see what it measures when clamped to a 1inch section of solid 12awg copper wire.Reviews of PeakTech here on EEVb are not that great.Seems like PT brand is sold as Southwire in North America ?

author: nytefog
author_rank: Newbie
timestamp: January 08, 2024, 09:55:14 pm
content: Lol, Jesus! I was just looking for some suggestions on others opinions regarding the best quality test leads for 2-wire DMM resistance measurements. I understand that a 4-wire/kelvin milliohm meter would be the best option for low resistance measure but unfortunately that’s not something I’m able to invest in at the moment.So, if I’ve read correctly the Probe master Spring Loaded Micro-Tip Test Leads (8152) give better resistance reading than probe master 8100 series “softie” (8017s).I’m mainly using them to take measurements of HVAC Inverter compress windings that have a low OEM specified Resistance range from 0.41- 0.72 ohms depending on the model.Thanks

author: bdunham7
author_rank: Super Contributor
timestamp: January 08, 2024, 10:16:42 pm
content: Quote from: nytefog on January 08, 2024, 09:55:14 pmYes, with proper technique you should be able to read those reasonably well using the 8152 or 8153 (which I have) and a Fluke 289 in Lo-Ohms mode. The stainless steel versions would not do as well because the contact resistance changes depending on how far you stick those sharp tips into the solder joint, if that's where you're putting it.

author: shapirus
author_rank: Super Contributor
timestamp: January 08, 2024, 10:23:00 pm
content: Quote from: nytefog on January 08, 2024, 09:55:14 pmAre you sure?Get aYR1035with axial probes and alligator clamps. It's a cheap, but solid performer in the mOhm (and up to 200 Ohm) range with one caveat: it measures with 1 kHz AC, so results will be off when the measured part has a sufficiently high inductance. It can also measure internal resistance of batteries.Trying to solve the inherent difficulties of 2-wire low resistance measurement by reducing the resistance of the probes is not going to yield a satisfying result anyway.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 08, 2024, 11:04:15 pm
content: Quote from: nytefog on January 08, 2024, 09:55:14 pmThe best you can probably buy will be silver plated copper end-to-end (with maybe the tips and nanna plugs gold plated), with leads that are as short as you can use.Your next option is just to find a reputable brand that can give you a real spec on how much ohms each lead really is, you then just use that # to offset your readings (which is just as good as 4W method).Next can possibly be someone you know can spec the leads for you, use that # to offset meter readings.Lastly, knowing the general properties of the leads (length, wire type, wire size, temp), you can use online claculator to drum up an approx ohmic value of the leads. You can even estimate nanna to tip, then add in tip ohms since tip is different size than lead wire.And final lastly. You don't really need "the best low ohms" leads. You just need to know what you have.

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 08, 2024, 11:18:41 pm
content: Without going to exotic extremes and costs -- and you made it pretty clear you're doing this to avoid the cost of proper low-ohm gear -- you're going to be hard pressed to do better than ProbeMaster probes. Another advantage of PM is the ability to order them in a 24" length, shorter than most other meter leads. I hear they'll also do custom sizes, but not sure if they offer that for single quantity orders, or what it might add to the cost.

author: bdunham7
author_rank: Super Contributor
timestamp: January 08, 2024, 11:22:24 pm
content: Quote from: Veteran68 on January 08, 2024, 11:18:41 pmThey build to order, except for popular stuff that they have on hand so the MOQ is typically 1 and there's no extra cost.

author: johansen
author_rank: Super Contributor
timestamp: January 09, 2024, 12:37:38 am
content: Maybe i got lucky but my UT61E+ measures 0.05 ohms with the leads it came with shorted together.

author: Kean
author_rank: Unknown
timestamp: January 09, 2024, 01:08:00 am
content: Quote from: shapirus on January 08, 2024, 10:23:00 pmThe YR1030/1035 are for battery internal resistance and voltage measurement, and thus use an AC measurement technique.The YR2050 is probably more appropriate, and does a DCR measurement. Mine outputs about 2V O/C and 90mA shorted. A pretty good price considering it includes the Kelvin test clips.

author: shapirus
author_rank: Super Contributor
timestamp: January 09, 2024, 10:30:31 am
content: Quote from: Kean on January 09, 2024, 01:08:00 amYes, I mentioned this. Even though it's primarily for batteries and uses AC voltage, it is still a good milliohmmeter. For parts/circuits whose inductance is insignificant produces very good readings (consistent with the results given by the method of passing a known current and measuring the voltage drop).Quote from: Kean on January 09, 2024, 01:08:00 amThanks for helping me spend another $34. Added to cart!

author: tggzzz
author_rank: Super Contributor
timestamp: January 09, 2024, 10:38:17 am
content: Quote from: nytefog on January 08, 2024, 09:55:14 pmA last! You bother to tell us the resistance range of interest.Now all you have to do is tell us what resolution and accuracy you needThe necessary equipment will be different depending on whether you want to know whether there is continuity, or to verify that the resistance is within that specified range, or ...If you think that low resistance leads are important, why don't you just do thecheap and simplething: make some from car jumper leads or welding cables? (Other people need not respond!)

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 09, 2024, 01:56:37 pm
content: I've heard of 'VOLT-NUTS', but now I realize there are also 'OHM-NUTS'

author: Kean
author_rank: Unknown
timestamp: January 09, 2024, 04:02:53 pm
content: Quote from: shapirus on January 09, 2024, 10:30:31 amThe price is great. I don't think you will regret it!With the Kelvin clips shorted I was getting about 1.2 mohm reading - but by moving the clips a bit I could get it to read about 600 uohm.I did not think I had many suitable low value precision resistors, but I found a few and measured them as follows.Vishay Z201 1 kohm 0.01% = 999.95 ohmVishay Z201 100 ohm 0.01% = 99.994 ohmTE CPF2512 100 ohm 0.1% = 99.976 ohmVishay 2512 0.1 ohm 0.1% = 0.10025 ohmVishay 2512 0.01 ohm 0.1% = 0.01008 ohmAmbient temp was about 26C. Readings were stable to +/-1 LSD.I'm happy with the above results. It is late and my 34465A isn't powered on, so I won't dig out my Keysight Kelvin clips for comparison.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 09, 2024, 05:51:20 pm
content: The application is 410-1000m-ohmAny 2W meter that has resolution to 1m-ohm, accurate to +/- ~3m-ohm, with just about any leads, should suffice.If the leads add up to 6m-ohm, that's not gonna make a diff in application.However, just get a set of leads from any vendor who can list a ohmic spec of the leads, you can then simply offset meter reading accordingly, making the documented reading more accurate.Or, take the leads you have and have them tested by someone who has a 4W and can read accurate to 1m-ohm.

author: 5U4GB
author_rank: Super Contributor
timestamp: January 10, 2024, 10:42:39 am
content: Quote from: shapirus on January 08, 2024, 10:23:00 pmOr, if you're willing to splash out a tiny bit more, the DE-5000 ordered from Japan via eBay sellers is probably only around twice the cost of the PM probes and does a lot more than just mOhm measurements.

author: shapirus
author_rank: Super Contributor
timestamp: January 10, 2024, 10:58:34 am
content: Quote from: 5U4GB on January 10, 2024, 10:42:39 amThe specs say that it can do 4-wire measurement, but I can't see how: there are just two connectors (save for the capacitor testing terminals). Besides, I don't see that it comes with Kelvin clips.What am I missing?

author: Randy222
author_rank: Frequent Contributor
timestamp: January 10, 2024, 01:38:51 pm
content: Quote from: shapirus on January 10, 2024, 10:58:34 amThat DE-5000 is packaged in different ways. Some sellers include accessories and a case, others just sell the meter.I believe it does 4W using two nanna jacks because the nanna jacks are split?

author: NE666
author_rank: Frequent Contributor
timestamp: January 10, 2024, 07:10:48 pm
content: Quote from: Randy222 on January 10, 2024, 01:38:51 pmActually, it looks to be the other way around on mine. The 4-way test fixture accessories e.g TL-21plug into both the banana jacks and the capacitor slots at the same time. However, the male bananas are only plastic extrusions and therefore are there only to help physically locate and secure the fixture. The metal tangs which connect to the capacitor slots are formed from a double sided PCB and handle the 4-wire connection.

author: mwb1100
author_rank: Frequent Contributor
timestamp: January 10, 2024, 08:08:13 pm
content: The DE-5000’s 4 wire leads are very short alligator clips that are 4 wire only up to the clips (my understanding - I don’t actually have a DE-5000).There are YouTube’s showing how to replace the alligator clips with actual 4 wire kelvin clips.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 10, 2024, 10:33:01 pm
content: Quote from: tggzzz on January 02, 2024, 11:58:39 pmThe attached link should be required reading for anyone asking questions in a web forum, regardless of the topic.

author: tggzzz
author_rank: Super Contributor
timestamp: January 10, 2024, 11:38:16 pm
content: Quote from: schmitt trigger on January 10, 2024, 10:33:01 pmThanks

author: 5U4GB
author_rank: Super Contributor
timestamp: January 11, 2024, 07:44:33 am
content: Quote from: Randy222 on January 10, 2024, 01:38:51 pmThe 4-wire resistance measurement is done via the 5-contact slot above the banana jacks (two force, two sense, and ground), which accessories like the TL-21 plug into. There are the required four leads going to the alligator clips, the banana jacks are just plastic castings for support. So you are getting the real deal, it's just better laid out than the usual mass of leads everyone expects.

author: mawyatt
author_rank: Super Contributor
timestamp: February 06, 2024, 06:10:12 pm
content: Quote from: 5U4GB on January 11, 2024, 07:44:33 amThe banana jack connectors on the DE-5000 have unique split conductor types, we've never seen these before. They have the Force and Sense conductors in the top and bottom on the banana jack.Anyone know where one can get the split plugs for these unique split banana jacks?Best,

author: bdunham7
author_rank: Super Contributor
timestamp: February 06, 2024, 06:25:29 pm
content: Quote from: mawyatt on February 06, 2024, 06:10:12 pmFluke uses this arrangement on their 2x4W probes, but I don't know of an independent source for the plugs themselves.https://www.fluke.com/en-us/product/accessories/test-leads/tl2x4w-ptii

author: tooki
author_rank: Super Contributor
timestamp: February 08, 2024, 08:11:02 pm
content: Quote from: mawyatt on February 06, 2024, 06:10:12 pm”Top and bottom” are very ambiguous terms, in that this can mean several different arrangements.Split banana jacks are common for multimeter plug detection. Those jacks are split lengthwise (along the axis), i.e. two half-moon halves of a cylinder.Do you mean that, or do you mean split into rings (perpendicular to the axis), like a headphone plug? (That’s how the Fluke ones are, as I understand it.)

author: bdunham7
author_rank: Super Contributor
timestamp: February 08, 2024, 08:20:25 pm
content: Quote from: tooki on February 08, 2024, 08:11:02 pmThe Fluke 2X4W plugs (and jacks) are not axial, they're split down the middle. On the bench meters this means right and left, but given how the jacks are oriented on the DE-5000 the same arrangement would be top and bottom, meaning as you look at the meter from the front. Split jacks you can find elswhere, but split plugs I've never seen available.

author: tooki
author_rank: Super Contributor
timestamp: February 08, 2024, 10:04:23 pm
content: Quote from: bdunham7 on February 08, 2024, 08:20:25 pmWell that’s the thing, on the DE-5000 they are not split into top and bottom, it’s the left-right split typically found in multimeters. (What for is another question, since all their accessories connect via the flat blades and don’t use the banana jacks at all.)This shows the back of the PCB, a bit earlier shows the left-right split jacks from the front:https://youtu.be/ji-UT7HJm0Q?si=ClT3DW3KcJQdnAxK&t=552As for the Fluke, do you have firsthand experience with them, or are you going by info from elsewhere?FYI, coaxial banana plugs do exist:https://www.schuetzinger.de/en/products-und-solutions/test-and-measurement/kelvin-programme.htmlIn particular, on the data sheet for the big Kelvin clip, there’s a drawing of the plug:https://www.schuetzinger.de/files/kml_7852_kelvin_191217.pdfUnfortunately they don’t sell the plug alone, though they do sell the jack, so that you can use their clips.

author: armandine2
author_rank: Frequent Contributor
timestamp: February 08, 2024, 10:24:25 pm
content: https://www.eevblog.com/forum/beginners/looking-for-a-esr-meter/25/I thought there was a picture of this somewhere

author: bdunham7
author_rank: Super Contributor
timestamp: February 08, 2024, 10:27:50 pm
content: Quote from: tooki on February 08, 2024, 10:04:23 pmIf the contacts in the jack are aligned with the pins as seen on that PCB then that would not be compatible with the Fluke 2X4W plugs as the split is rotated 90 degrees. So it appears to be not top and bottom as stated bymayawatt--unless the jack is constructed differently that what we expect. I don't have one here to look at.I have the Fluke 2X4W probes and two different meters that use them. It's not practical to take pictures, but I can see the split in the jack and the design of the plugs. Essentially the plug is a plastic cylinder with two springy contacts protruding from either side.

author: slugrustle
author_rank: Frequent Contributor
timestamp: February 11, 2024, 02:46:36 am
content: Quote from: nytefog on January 02, 2024, 11:41:06 pmSeems like a sensible question, focused, specific, politely phrased, explains that 4-wire is out of the picture. The author must be new here.Fast forward to Reply #45:Quote from: nytefog on January 08, 2024, 09:55:14 pmWelcome to EEVblog forum! Where people come to post opinions tangentially related to topics, not to answer questions as posed. And especially not to answer questions as posed after reading them carefully, lol.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2024, 11:38:36 am
content: It seems to me the questionwasanswered, making room for the remaining discussion.OP wanted to know if there are any 2W test leads with better performance than what they already have. Consensus is “no, OP already has the best on the market.”

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: February 11, 2024, 05:37:10 pm
content: Quote from: johansen on January 09, 2024, 12:37:38 ammy unit ut61E+ measures 0.06 with the tips short and my old and faithful unit ut61C 0.7, I can't complain the reel fincion does the restin spanishmi unit ut61E+ mide 0.06 con las puntas en corto y mi viejo y fiel unit ut61C 0.7, no me puedo quejar la fincion reel hace el resto

author: jackobo
author_rank: Contributor
timestamp: March 19, 2024, 12:41:41 pm
content: BST 050jp leads at alixprss, my GW gdm541 shows 0.05 Ohm

author: shapirus
author_rank: Super Contributor
timestamp: March 19, 2024, 12:55:24 pm
content: Quote from: jackobo on March 19, 2024, 12:41:41 pmReally good leads btw, with sharp andthintips, and no guard rings, so very convenient and excellent for electronics. Proper silicone wires, of course. The only cons is hard plastic probe body, I'd prefer some softer material. And maybe it makes sense to add some heat shrink insulation on the tips to leave only a short length exposed to prevent accidental shorting of things. The coating on the tips does wear over time, but they are sold with a set of spare tips, and more spare tips can be bought separately.

author: Randy222
author_rank: Frequent Contributor
timestamp: March 19, 2024, 05:36:50 pm
content: Why do we need ultra low ohms leads? A good meter should be able to apply an offset (REL or a memory function) for test leads shorted ohms.Look for meter feature rather than trying to buy "expensive" leads.

author: Fungus
author_rank: Super Contributor
timestamp: March 19, 2024, 07:01:34 pm
content: Quote from: jackobo on March 19, 2024, 12:41:41 pmSuperconducting leads!https://www.aliexpress.com/item/1005002587720896.html

author: ebastler
author_rank: Super Contributor
timestamp: March 19, 2024, 07:07:41 pm
content: Quote from: Fungus on March 19, 2024, 07:01:34 pmAnd with little CAT III 2000V, 20A crocodile clips!That superconductivity clearly pays off...

author: shapirus
author_rank: Super Contributor
timestamp: March 19, 2024, 07:15:30 pm
content: Joking aside, these leads are good. There seem to be a new type now, with shorter non-coated tips, I haven't tried those. I'm using the other type, with the longer, coated tips....and yes, the stock Brymen tips are resting on the shelf. Yes, these BST leads are better for me. No way I'm going back to thick tips.

author: MtnMike
author_rank: Newbie
timestamp: December 25, 2024, 05:55:36 pm
content: I've had the same issue with Fluke TL71 Test leads. Most sets I have measure about 0.04 ohms per lead. I have 2 leads that measure high. One at about 0.30ohms and another at 0.12ohms.I finally got around to investigating it yesterday, as I just don't use the high resistance leads.I ran 10ADC through each lead and used a thermal camera to find the issue. I let them warm up about 5 minutes and both leads had a hot spot in the handle right at the finger guard about 113F.So, obviously a bad connection issue.I then measured the leads again after running 10A through them and now they both seem to be good and measure about 0.04 ohms.So, they are probably a crimped connection to the probe tip that was oxidized and the current broke it down. It will be interesting to see if they keep the low resistance or fade back up over time.

author: johansen
author_rank: Super Contributor
timestamp: December 25, 2024, 06:11:01 pm
content: Quote from: MtnMike on December 25, 2024, 05:55:36 pmProbably a soldered connection but due to use, the strands are breaking.

author: MtnMike
author_rank: Newbie
timestamp: December 25, 2024, 06:37:57 pm
content: The lead with 0.30 ohms was unused. I have repaired many leads over the years due to strands breaking in and round the connectors. Those give intermittent readings, the usual issues.These leads were not intermittent, solid readings all the time.They could be soldered, I never repaired on at the probe tip wire connection, so I don't know. I thought that too, I may have just reflowed cold solder joints.

author: Fungus
author_rank: Super Contributor
timestamp: December 25, 2024, 10:33:44 pm
content: Quote from: MtnMike on December 25, 2024, 05:55:36 pmThey just needed to be burnt in.

author: indeterminate
author_rank: Regular Contributor
timestamp: December 26, 2024, 02:11:38 am
content: I think that they are just badly crimpedI have a pair that if you hang onto the probe and lead and give them a little tug the resistance drops

author: bdunham7
author_rank: Super Contributor
timestamp: December 26, 2024, 02:13:49 am
content: Quote from: indeterminate on December 26, 2024, 02:11:38 amProbe Master solders their test lead for this very reason.

author: 5U4GB
author_rank: Super Contributor
timestamp: December 26, 2024, 04:12:35 am
content: Quote from: Fungus on December 25, 2024, 10:33:44 pmJust be aware that the process makes them directional so from now on you can only use them to measure DC currents and voltages.