LCR Cal Test PCB - Page 1
Forum section: electronics / testgear

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 04, 2024, 10:16:03 pm
content: A bunch of us have been comparing the accuracy and ranges of our LCR meters, and to compare to the "official" cal cert Martin72 received with his ST2830, I made my own test report and a test PCB to go with it.I've been through 3 out of 4 versions of the board (skipped the 3rd after learning how to test dissipation factor). I'm now getting ready to make a 5th, and hopefully final version of the board. I could use some ideas and a little insight in finishing the last design.There's some extra space on the R side, as I recently removed 1GΩ and 100MΩ test points. If somebody things I should keep one or both, let me know why you feel that way. I'm also considering adding 1pF back onto the C side, but it's lower than typically useful on these tests, but I do know the Shannon ST42 can test it fine.Currently, my biggest question is finding a more reliable method for kelvin clip test points. What I have now is 3mm pads on top and bottom of the PCB running to the test components. For my kelvin clips to get a good connection, I have to add solder to both points around the board, and the resulting connection isn't amazing. It requires a little wiggling to get the best connection. I want something more stable.Here's what the board design looks like currently:

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 04, 2024, 10:18:36 pm
content: Here's the most recent example of my test done with V4 of the board.

author: Martin72
author_rank: Super Contributor
timestamp: July 04, 2024, 10:31:06 pm
content: That doesn't look too bad.Personally, I would stop at 10mH, 100µF, 1M Ohm.And start at 100nH, 10pF and 1 Ohm.While finding very small tolerances for resistors is not a problem, I had not found anything below 2% for capacitors, for example, and nothing below 5% for most coils.What did you use, where can you find it?

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 04, 2024, 10:44:43 pm
content: Quote from: Martin72 on July 04, 2024, 10:31:06 pmThe first reason I got into testing inductance is for making Wah Wah pedals. Those inductors range from 500mH to 700mH, so I'll always include them. How accurate they are on their own doesn't matter. Once the board is finalized, it can be calibrated and then the calibrated value is the only thing that matters. I also test guitar pickups, and the (standard) ones I've done range between 3 to 5 Henries so far.I'll put together a BOM including the parts. Everything except the wah inductor was from Mouser. Most, if not all (remaining) resistors were 0.1%. The rest is probably along the lines of what you said. High values tend to be worse, but I'll buy extras (including higher values) and find what tests to the desired value, and go with that in the end. Seeing 75µF or so when it's supposed to be 100µF is annoying.I still think finding a better method for connecting kelvin probes is high priority. Or scrapping the kelvin probes entirely, whichever works better. 😉 I think having the lower values isolated might be enough on their own. I can test this by using the kelvin clips only touching the board top test points. Still though, I would prefer a better kelvin option.I've seen some smaller pins that might work, but I dunno if that's the best way, especially if they get bent over time.Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: July 04, 2024, 10:54:51 pm
content: The pins that DMMCheck Plus uses are quite stable, I can still reach them easily with Kelvin clamps.

author: tautech
author_rank: Super Contributor
timestamp: July 04, 2024, 10:59:27 pm
content: Quote from: KungFuJosh on July 04, 2024, 10:16:03 pmSMD test points ?https://www.keyelco.com/category.cfm/Test-Points-Tips-Probes-Clips/Test-Points-Surface-Mount/id/523

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 04, 2024, 11:03:53 pm
content: The first version of my test PCB had similar style turrets as the test points, but people complained about that not being a kelvin connection. For a kelvin connection, there needs to be two connectors for each side of each test point.Doing a top mounted pair of pins or other connector is the idea. But the single connection per test point is not ideal.Here's the old V1 board:

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 04, 2024, 11:06:00 pm
content: I should mention my plan is likely to change to two parallel traces run to each test point (instead of top/bottom traces). The question is the best connectors to use with them. Or if somebody has a better idea, I'm open.

author: Martin72
author_rank: Super Contributor
timestamp: July 04, 2024, 11:14:13 pm
content: Hi,QuoteDoesn't make sense in my eyes.You can only connect 2 points with normal Kelvin test leads anyway.The four-wire measurement is used to eliminate the cable lengths.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 01:01:03 am
content: Quote from: Martin72 on July 04, 2024, 11:14:13 pmDoesn't make sense to me either, except that other members here said the same thing, but also for eliminating the traces going to the test points. There was discussion about it when I first posted the picture of the V1 version of the test board in the 2830/2832 improvement thread. If I misunderstood something, or I'm missing something else, I'd love to be educated on the subject. But not enough to go to you know where. 😉😉

author: mawyatt
author_rank: Super Contributor
timestamp: July 05, 2024, 02:38:02 am
content: Here's an idea where the Kelvin Clips "clamp" to Plated Thru Holes in the PCB by "Splitting" open the Kelvin Clips this allows the Sensing Port to take place where the Force Current enters the Thru Hole DUT contact lead pad, or the SMD DUT pad, thus "sensing" very close to the DUT leads/termination.You should include an "Open" and "Short" for LCR Calibration and would expect to give good results down into the tens of milliohms impedance regions but haven't verified such.Best,

author: shabaz
author_rank: Frequent Contributor
timestamp: July 05, 2024, 06:56:31 am
content: Nice-looking board.QuoteGreat ideas. Also the trace lengths should be similar-ish from component to component, and (if there's space) a U.FL pad could be interesting per component, so that users could optionally use the board with VNAs too.Another thing could be to split the SMD pads (so that there are four pads for each component), i.e. have the kelvin connections separated all the way to the pad.Also, instead of the silkscreen legends, maybe silkscreen white filled rectangles could be interesting, so that people can populate with whatever components meet their needs, and a permanent pen can be used to label the components.Another idea could be to retain the current text silkscreen, but ensure there's a faint box outline where a user could apply a printed sticker if they wish to change the value.Anyway, I have no idea if these extra suggestions are any good, or they might be overkill, possibly too much effort if the board is already mostly designed, for the small additional benefit.

author: jchw4
author_rank: Regular Contributor
timestamp: July 05, 2024, 08:16:21 am
content: Quote from: Martin72 on July 04, 2024, 10:54:51 pmI found that I get different readings on the 1uH inductor depending on how I put the clips. The mounting screw in the corner doesn't allow symmetric clip positioning for the most common clip size.Looking at your picture, I guess that the correct way for that part is to put the left clip "from the front" and another one "from the right side" kind of "behind the screw".BUT the vendor does not specify that and we have no information on how they make connections during the calibration.You may suggest using smaller clips for that part, but the funny part is that I am using BK Precision TL8KC1 clips with my DE5000.And I guess that BK Precision is shipping exactly the same clips with all their LCR meters including the one that DMMCheck Plus is using for the calibration...As you now have quite a few LCR meters, you probably have a few different clips too. Could you measure that inductance with different clips and share the result?

author: Phil1977
author_rank: Frequent Contributor
timestamp: July 05, 2024, 08:38:23 am
content: Very nice PCB - if there is a possibility to get one in Europe I´d like to buy one.From my point of view it´d be perfect if there would be two additional "Sense"-testpads directly next to each reference component. That way you could connect your 4W-sense-probes as perfect as possible and everything else on the PCB stays the same.For usage of the 4W-Kelvin-crocodile clamps the vertical test pins should be fine. Then they only compensate the test cables and not the PCB influence, but for most of the values that should be okay.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 04:29:54 pm
content: Quote from: mawyatt on July 05, 2024, 02:38:02 amI love it, and not just because I was hoping somebody smarter than me would suggest it. 😉 PTH vias shaped appropriately I think would work great, and I much prefer that over using pads as I am currently.Quote from: mawyatt on July 05, 2024, 02:38:02 amI love this idea too. I hadn't thought much about it, but I recall your advice on doing similar for the SMT fixture on our LCRs.Quote from: shabaz on July 05, 2024, 06:56:31 amThat's an interesting idea. However, I think if it has any benefit, it's beyond what's needed for this specific test. The idea gives me two concerns: 1. that it would reduce the solder pad area; 2. That the 2 pads being soldered to the same end of a component doesn't seem like there would be any significant difference than connecting both kelvin connections to the same pad (as they are now). I could be wrong of course, but for the purpose of this PCB, regular pads seem fine.Quote from: shabaz on July 05, 2024, 06:56:31 amI haven't decided what I'm going to do with this when it's done done. I'll at least share the Gerbers so others can have them made. I think if people want to do stickers, it doesn't really matter what I leave on the silkscreen.All ideas are appreciated! Thank you.Quote from: Phil1977 on July 05, 2024, 08:38:23 amThank you! As I mentioned above, I'll at least be sharing the Gerbers when this is done. Then anybody can order 5 boards for much less than the cost of shipping to Europe.Yes, others have mentioned that they would prefer having separate connections for each component. Personally, I don't like that idea...because I'm lazy and testing already takes too long. For small values where that might have an effect, I agree (and it's already implemented that way). But for most of the stuff, it makes no difference.If you check my cal test results I posted above, you'll see that the tweezers and the bench LCR were in excellent agreement for most items. It's probably useful to mention that the tweezers tested components directly, and did not use any of the kelvin connection test points. For the results being as close as they are, I think the logic behind my connection scheme is good enough for me. 😉Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 04:40:01 pm
content: Here's a question: Does anybody else want a couple additional values?I was thinking about adding 1pF back to the board.Also was thinking whether what I have for resistance is enough. It used to have 100MΩ and 1GΩ, but those values aren't that useful. I'm thinking the real estate would be more useful for adding 1pF in.ETA: I know it doesn't matter if people relabel it, but maybe somebody wants more things available in a specific category.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 05, 2024, 04:57:12 pm
content: unless an huge demand, i think your kit is fine, people will never be 100% pleased, your not down to metrology levelsif you are satisfied, that's what matters, turret test points are good enough ...my 2x kelvin test clips are shorting only on the same connection once they are closed ... no need for 4 separated clips ....others will be able to do their test rig ...thks

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 05:40:53 pm
content: Thanks! I have no interest in getting to metrology levels, that's why I posted in this section. 😉I am going to convert to Mike's idea of PTH vias for the kelvin connectors. I like that it's more accurate, less work, and costs less since there's no need for expensive turrets.

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 07:40:04 pm
content: Quote from: jchw4 on July 05, 2024, 08:16:21 amYes, there are a few now, but they are basically the same because they always have the same clips.

author: mawyatt
author_rank: Super Contributor
timestamp: July 05, 2024, 08:00:35 pm
content: The Tonghui Kelvin Clips are slightly smaller than the generic types (we have a bunch of these also), and of much higher quality and have embedded Hcur, Hpot, Lcur and Lpot Labels on the Clip handles.Best,

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 08:22:40 pm
content: The ET3502 makes a good impression in the few measurements I have taken, and if this continues to be the case, I will keep an eye out for other cables.Maybe I'll buy some from Sourcetronic.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 08:35:53 pm
content: Does anybody think I need bigger than a 2mm x 5mm hole for each of the kelvin tips on their random kelvin clamps?

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: July 05, 2024, 09:05:32 pm
content: Make sure you consider tempco.Most ceramic capacitors have bad temperature coefficient, and you should probably get C0G/NP0 capacitors or film capacitors. Your standard X5V or whatever capacitors won't be accurate if the temperature changes.I'm not sure what the temperature coefficient for inductors is. Might have to check that too

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 09:07:27 pm
content: Thank you. They are all C0G/NP0 MLCC for that reason, except where the values are too high, then they're X7R.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 09:10:32 pm
content: Quote from: shabaz on July 05, 2024, 06:56:31 amI'm curious, as I've never had a VNA. What about this board would be useful to VNA users?

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 09:12:15 pm
content: I always like to use these golden support points for my PCBs, they are suitable as test pins as well as wiring support points.Narrow design but still very stable.Edit: Pic added.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 10:06:04 pm
content: This is the new kelvin clip connection test point I made in Kicad. The opening is 1.8mm x 4mm with a 2mm gap between openings. I'll keep it this size if it fits, otherwise I'll drop it down a little.Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 10:17:44 pm
content: I wonder how long something like this can last.

author: shabaz
author_rank: Frequent Contributor
timestamp: July 05, 2024, 10:18:48 pm
content: Quote from: KungFuJosh on July 05, 2024, 09:10:32 pmIt's almost the same thing as the LCR meter, but the implementation is different internally. Unlike an LCR meter, one downside is that the sweet-spot for accuracy is far narrower, but on the positive side, the measurement frequency range can be large (to GHz and beyond if desired, although the minimum frequency is often say 10 kHz or 50 kHz, it would be rare for it to function down to say 50/60 Hz, although some VNAs can be made to operate to such low frequencies).Instead of Kelvin clips, there are just two-wire connections using coax usually. The way it works is that the VNA causes an AC voltage to be applied at a frequency, and some of the signal reflects back from the device-under-test if it doesn't look like exactly 50 ohm at the given frequency, and the VNA measures the reflection and compares it internally with what was sent (in terms of signal level and phase), to make its internal calculations. After a frequency sweep, the output can be plotted in various selectable forms.The photo shows a DIY board that is similar to your test board, but only with RF connectors and no kelvin clip holes. My board has the open and short (as @mawyatt mentions), but for a VNA a 50-ohm termination is also needed for the calibration, whereas LCR meters often don't need that. If your board was used with a VNA (for say measurements from tens of kHz to tens of MHz), then a 50 ohm resistor location (could be 49.9 ohm, or two 100 ohm in parallel) would be good.My board only has space for one component that I have to desolder if I want to measure a different component. Eventually the SMD pad can tear off due to the repeated soldering operations, so it isn't that good unfortunately.I made this board by copying an existing TI board Gerber files (it was a reference design for PCB antennas, but I deleted the antennas from the Gerber files and copied the 'open' portion to make the DUT area (with the solder mask removed in the Gerber files from the end of course).The chart shows example output for a particular inductor.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 10:26:19 pm
content: Quote from: Martin72 on July 05, 2024, 10:17:44 pmIf made with a good copper weight/ENIG, I'm sure it would last fine. The connection holes can be cleaned and a thin layer of solder added eventually if needed. If you drag the kelvin clips out tight and hard a few hundred times, that might be a problem. If you're gentle, I don't see why it would ever be an issue. I probably won't use it even 50 times. Not all of use have 30 LCRs. 😉

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 10:28:34 pm
content: I will use my test pins.That leaves the question of the components.Tight tolerance resistors are a dime a dozen, with capacitors it's a different story (2%), with coils the same (5%).

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 10:30:00 pm
content: Quote from: shabaz on July 05, 2024, 10:18:48 pmThank you for the explanation. Between your explanation, and your example, I don't think my board would be great for that. A modified version of it might though.How many components/values do you want to test? I dunno if that crazy plated area on your board is needed or not, but if it is, a multi-component board could get quite large. If it's not needed, then I would need to know the values and component types that would be useful on a VNA variant of the test board.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 10:31:11 pm
content: Quote from: Martin72 on July 05, 2024, 10:28:34 pmlol, fair enough. Perhaps I'll make a hybrid connector version so people can easily make that choice. What size mounting hole do you need for those cute little pins?

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 05, 2024, 10:42:14 pm
content: Here it is with 1mm holes, I'll adjust to what size you need of you like the idea.

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 10:54:33 pm
content: 1mm could fit, but I'll measure it again tomorrow.

author: mawyatt
author_rank: Super Contributor
timestamp: July 05, 2024, 11:27:23 pm
content: Quote from: Martin72 on July 05, 2024, 09:12:15 pmThat image with the Blue components looks like a Twin T Notch Filter?Best,

author: Martin72
author_rank: Super Contributor
timestamp: July 05, 2024, 11:32:18 pm
content: Jepp,I had designed it according to your idea, for the Bodeplot, if you still remember it.

author: mawyatt
author_rank: Super Contributor
timestamp: July 05, 2024, 11:55:24 pm
content: Short term memory failing fastHowever, saw the 4 Blue Caps, and 4 resistors, thinking the Blue caps look equal size/value (can't tell about Rs tho), so what passive network (didn't see any active stuff) could this be??Should produce nice notch if the Caps are matched assuming Rs are typical 1%.Best,

author: Martin72
author_rank: Super Contributor
timestamp: July 06, 2024, 12:02:51 am
content: I can show it again in the 3000X HD thread, but not here.

author: shabaz
author_rank: Frequent Contributor
timestamp: July 06, 2024, 12:26:16 am
content: QuoteThat board is intended for up to a GHz, but realistically for measurement up to some tens of MHz, if not a lot of accuracy is wanted, then even a solderless breadboard is fine. Often users don't mind if there's (say) 5-10% error, because inductors and capacitors have tolerances anyway, and some circuits can trim that out. The photo shows a board that comes with some NanoVNAs, used for through-hole components.Personally I don't need a lot of component positions, just as long as 0603 up to 1210 or so components can fit. But no need to design specifically for these requirements, I was just thinking out loud in case it was useful for you or others too. Maybe it's a bit too niche to add to your existing layout, unless you're planning to explore with a VNA at some point.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 12:42:33 am
content: Ha, I bought some of those boards, built them, and forgot I had them. I hate 0603, I try to avoid them. I'm too old and wear glasses. 🥸

author: tautech
author_rank: Super Contributor
timestamp: July 06, 2024, 12:59:32 am
content: Quote from: KungFuJosh on July 05, 2024, 10:31:11 pmAfter spotting the reply from shabaz, another thought for pins came to mind.TH turned IC pins we sometimes use instead of IC sockets < plentiful and cheap.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 03:37:28 pm
content: I'll keep it simple and make the hybrid option I shared above. I just need confirmation on the hole and pad sizes. That way anybody can do what they like.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 06:26:09 pm
content: I took a look at these pins from keyelco:https://www.keyelco.com/userAssets/file/M65p104.pdfSeems like a 1.5mm hole is better, so this is what I'm going with unless somebody has strong feelings about it:

author: mawyatt
author_rank: Super Contributor
timestamp: July 06, 2024, 06:35:18 pm
content: How are you going to arrange these thru component holes so you can use the Kelvin Clips on each end of DUT. If the DUT is a leaded component then you'll need two holes for it that are separated by the DUT spacing, then at each end/hole you'll need the Force and Sense holes for the Kelvin Clip.Needs to look and work something like our sketch earlier.Best,

author: mendip_discovery
author_rank: Super Contributor
timestamp: July 06, 2024, 06:54:18 pm
content: Quote from: Martin72 on July 05, 2024, 10:28:34 pmI have often wondered this, as I don't think I want to go to the effort of the large standard resistors but at the same time I would like some with good properties that mean consistency and little drift over time.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 06:58:10 pm
content: Quote from: mawyatt on July 06, 2024, 06:35:18 pmIt's mostly going to be the same as V4 board pictured above. The V4 board has a 4mm SMT pad on top and bottom of the board running to each test point, with the bottom traces connecting via a hidden via near each component. The issue was only making the physical connection with the kelvin clips more reliable.Instead, for the new version, I'll keep everything top side in parallel and eliminate the extra vias. As you can see from the test results, accuracy was great (at least for my needs). I'm not trying to get anywhere near metrology craziness. But considering the ST42 was direct to component, and the ST2832 was via the test points, that's certainly close enough for me. If any of the disagreements were related to the connection type, that would most likely be the fault of the inconsistency with the mechanical connection on the top/bottom pads that required solder to make the connection work.I'll still be adding the open/short points as well for calibration before testing.If you have any opinion about the above, please share. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 07:01:24 pm
content: Quote from: mendip_discovery on July 06, 2024, 06:54:18 pmThe resistors were the easiest and mostly the cheapest parts for the board. 0.1% at 10 to 15ppm for SMT resistors or 0.1% and 25ppm for the CMF industrial THT resistors. The rest of the board is trickier.

author: Martin72
author_rank: Super Contributor
timestamp: July 06, 2024, 07:02:08 pm
content: @Josh:1mm drill hole..

author: mawyatt
author_rank: Super Contributor
timestamp: July 06, 2024, 07:06:44 pm
content: Quote from: Martin72 on July 05, 2024, 09:12:15 pmYour layout might not work with Kelvin Clips as they will interfere with each other near the handles (overlap), better to rotate the terminals 90 degrees so the Kelvin Clips can be on each opposite sides of the DUT facing away from the DUT.Best

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 07:08:54 pm
content: Quote from: Martin72 on July 06, 2024, 07:02:08 pmWill 1.5mm still work for you? I don't mind changing it, do you have the sheet for the pins?

author: mawyatt
author_rank: Super Contributor
timestamp: July 06, 2024, 07:17:36 pm
content: Quote from: KungFuJosh on July 06, 2024, 06:58:10 pmFor the Kelvin Clips to mount directly to thru holes Force and Sense, you want the holes 90 degrees to the DUT and on the outside of DUT lengthwise. You need enough spacing between the Hcur Force Hpot Sense on one Kelvin Clip to the Lcur Force and Lpot Sense on the other Kelvin Clip. These Clips need to be mounted with thin side 90 degrees to the DUT length, otherwise the handles will interfere. The Kelvin Clips we have are ~18mm thick across the handles.Make a mockup out of cardboard and you'll see what we meanBest

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 07:25:04 pm
content: Quote from: mawyatt on July 06, 2024, 07:17:36 pmThank you, I totally understand regarding the spacing issue. It will be most important for the low value components that get independent connections for both sides. It will be less of an issue for the rest, but I'll keep it in mind for the placement.OTOH, we could just connect with one kelvin clip on each side of the PCB. No space issue that way! 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 06, 2024, 11:57:31 pm
content: Here's a tentative layout with the new connectors. I haven't run any traces yet. I think angling the kelvin clips a little bit should remove any physical limitations given the space. Currently the board is 150mm x 120mm, and I'd prefer not to go any larger.Thoughts?Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 07, 2024, 01:58:45 am
content: The "Open & Short Cals" must include the traces and DUT pads to be accurate.For example, the 1, 10, 100pF must have an accurate "Open Cal" to remove all the parasitic trace & pad capacitance to accurately resolve the actual DUT capacitance.For low value resistors like 1, 10, 100 ohms, these require an accurate "Short Cal" to remove the parasite trace and pad resistance, same for low valued inductances like 10, 100, 1000nH.The "Split Kelvin Holes" are for the low R, L & high valued Cs, maybe consider going to 100 ohms, 1uH, and above 10nF.No need for the "Split Kelvin Holes" for the low valued Cs (use 2 Kelvin Hole Open Cal here), you want this for the high value Cs where ESR and ESL are important, like above 10nF.Move the Kelvin Holes closer to the DUT on the Non-Split Kelvin fixtures since the traces are not compensated, keep traces as short as possible.Since you have plenty of space, maybe locate Open and Short Cal near the high and low Impedance valued components on each side by R, L, and Cs.Also, why the small thru holes on the Kelvin Clip Thur Hole tops?Those were for the terminals if used.Avoid thru holes if possible, they add unwanted additional resistance and inductance to the fixture parasitics.For low Z components try and "carry" the Kelvin connections right to the DUT Pad with low trace resistance for the Force trace, Sense trace shouldn't matter, then for the high Z components "carry" a single short length trace from the Kelvin Thru Hole to the DUT Pad and minimize parasitic capacitance.Best,

author: mawyatt
author_rank: Super Contributor
timestamp: July 07, 2024, 02:53:00 am
content: Josh,Another way of thinking about the above is, the high Z components will experience higher voltages (low currents) during test and thus small shunt parasitic capacitance matters, whereas for low Z components will experience higher currents (low voltage) and small series parasitic resistance & inductance will have a direct influence.This is why "carring" the 4 Port Kelvin Connection to the DUT contact point is important, it helps by sensing the DUT Voltage at the DUT point of contact thus partially removing the effects of parasitic fixture (and cable) series resistance and inductance.We must also remember that our Lab Grade LCR meters measure complex Real and Imaginary DUT Voltage and Current, then compute the desired display DUT parameters and why getting the DUT thru current and voltage across DUT is paramount in achieving accurate and repeatable resultsBest,

author: Phil1977
author_rank: Frequent Contributor
timestamp: July 07, 2024, 11:45:38 am
content: It´s really academic to discuss if smaller or larger values need 4W-wiring. There are good reasons to do both, but I´d be very satisfied with such a board that has 4W-connections only for low C, low L and low R - as depicted in the latest rendering. I think if you need more accuracy, you should take dedicated boards for each value and also avoid common return lines - but that contradicts the purpose of a handy and convenient quick test board.Last but not least: Please make the penguin bigger again

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 03:13:38 pm
content: Quote from: mawyatt on July 07, 2024, 01:58:45 amThey will, but I'll see if I can make them the same size/length as the low value stuff. I downloaded your doodles from your previous reply, they were definitely helpful in understanding the setup.Quote from: mawyatt on July 07, 2024, 01:58:45 amI think this should be easy enough for those specific low value items. I know I could go much further with this and have separate connections for everything, at perfect lengths, with open/short cal for each section depending on pad sizes. However, that's not the purpose of this. This board is supposed to be a relatively quick way to test each range. I need to compromise between what's honestly very slightly better results and test speed. If I have to disconnect clips for every single measurement, that's time wasted. My impatience is far stronger than my desire for perfect accuracy. 😉Based on my previous board, which is certainly a lesser design than the direction this is going, only 1Ω was off from the ST42 direct to DUT connection, and only by 5µΩ.Capacitance was generally well agreed until 10µF and 100µF. Should I have those higher values separated from the string? It sounds like you're saying those high values need the separate connections for C, not the low values? Even 1pF or 10pF can be in the string? IIRC I added the separate points for 1pF and 10pF because of issues with them when in the string with the rest.Besides that I need to reduce the distance between the DUTs and the terminals. No problem.Quote from: Phil1977 on July 07, 2024, 11:45:38 amYou're right, of course, but I enjoy learning from Mike. If I'm understanding him correctly, it seems that I should have the separate connections for C at the higher values instead of lower values. If that's correct, it's not a big deal. As long as I don't need separate stuff on all of them.Quote from: Phil1977 on July 07, 2024, 11:45:38 amAbsolutely! 🤣Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 07, 2024, 04:26:49 pm
content: Having separate Force (Hcur & Lcur) and Sense (Hpot & Lpot) connections for high value Cs (low Z) will allow better ESR and ESL evaluations. Also for low Cs (High Z) consider just single trace to DUT ends, this reduces parasitic capacitance.One reason you may be seeing the discrepancy between the LCR and Tweezers for high value Cs is these are likely the high dielectric types which have a high voltage/temp/hystersis/age sensitivity unless they are NP0/C0G types. This sorta implies that the Tweezer/LCR excitation voltage needs to be the same as well as temp and the readings repeated back and forth between the two instruments with cap leads shorted in between the swaps. Getting repeatable results with high valued ceramic caps is almost a waste of time unless they are NP0/C0G, electrolytics are a little better but still difficult wrt repeatability.For higher C values (up 10/100uF) you might consider Film types as even the cheap Mylar caps are much better wrt to repeatability, Polypropylene is better and Polystyrene are excellent.Awhile back we considered making a somewhat small PCB with a few Cs and Rs, no Ls tho. This would serve for some quick checks but would be designed such that it could be considered for more serious verification. Even considered including a thermistor on PCB so temperature could be recorded. One of these PCBs could be sent around for folks to compare results with various instruments, which would be interesting indeed!!If we ever get enough time and things calm down we'll consider rolling one of these, but for now it's on the back burner. Of course your project is heading in the same directionAnyway, hope this helps.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 05:11:59 pm
content: Quote from: mawyatt on July 07, 2024, 04:26:49 pmOkay, so single traces for the two independent low value Cs. Split traces for the high value Cs with separate connections. I can do that, I'll get over the 3 extra clip movements. 😉I'm using NP0/C0G for all the Cs that those are available for. I'm using X7R for the larger caps, 10% X6S for the 100µF, and a 20% tantalum for the 1mF. Switching to other options becomes difficult either due to space or cost or both. I will look at a couple alternative options for the 10µF & 100µF caps. I may keep them as they are and measure them off board to find the desired value rather than the stated nominal value before installing.You make a good point regarding the test voltage. The tweezers test at 1Vpp and the ST2832 at 1Vrms. I may try those C values that disagreed with matched test voltages and see how they look.Thanks as always,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 07, 2024, 05:38:55 pm
content: Tantalums are usually not too bad, however the 100uF should be in X7R if possible, maybe parallel a few up for ~100uF, or just use a Tantalum, it should be better than the higher K dielectrics!!Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 05:51:22 pm
content: Quote from: mawyatt on July 07, 2024, 05:38:55 pmHow about this guy? F950J107KAAAQ2

author: mawyatt
author_rank: Super Contributor
timestamp: July 07, 2024, 06:30:46 pm
content: Kyocera is a good brand, never had any problems with their components. You might consider a higher voltage rating like 10V, and/or a leaded capacitor.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 06:37:42 pm
content: Quote from: mawyatt on July 07, 2024, 06:30:46 pmTest voltages are typically between 0.354V to 2Vrms. Do you often test with higher voltages?ETA: size is my only concern. If they fit at 10V, that's fine with me as long as they don't cost 10x as much. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 07:15:47 pm
content: Here's an updated version of the board with the traces ran.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 09:06:41 pm
content: Here's a suggest BOM for V5. Many of the parts have been used previously, some are new. I didn't like some of the inductors, so I changed some of them out.Everything is at least 10V except the 1mF cap which is 6.3V.Feedback is welcome. Try not to cause too much work. 😉Thanks,Josh

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2024, 09:12:51 pm
content: My 2c worth, move all the value labels further away from the test points and/or increase the font size.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 09:26:17 pm
content: Quote from: mawyatt on July 07, 2024, 04:26:49 pmCorrect as usual. The biggest discrepancy was the "100µF." I retested with 350mVrms on the ST2832, and 1Vpp on the ST42:ST2832: 68.0038µFST42: 68.06µFMuch better agreement! Previously they were off by 4µF.Thanks,JoshETA: I suppose when I get V5 of the board, I should leave the test voltages matching.

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2024, 09:28:04 pm
content: Quote from: tautech on July 07, 2024, 09:12:51 pmOh and add device tolerances, 0.1% etc.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 09:32:51 pm
content: Quote from: tautech on July 07, 2024, 09:12:51 pmNo problem,oldfriend. 😉Quote from: tautech on July 07, 2024, 09:28:04 pmThat might be an issue if other people build them with other parts.

author: Martin72
author_rank: Super Contributor
timestamp: July 07, 2024, 09:40:13 pm
content: Quote from: KungFuJosh on July 07, 2024, 09:06:41 pm1% capacitors ? Very good, I'm a bit surprised, I would have expected more from mica capacitors.I still have to catch up on the thread a bit, up to the point where it will be explain why a four-wire method is not executed for all values.With the resistors this makes immediate sense, with a tolerance of 0.1% for a 10K resistor for example, a few micro ohms make no difference.The comparatively high tolerances for the coils are unfortunately unavoidable if you don't want to build huge boards.The core makes the tolerance, roughly speaking, "better" would be air coils, but these become huge with increasing values.I also admire your work with KiCAD, I've tried it a few times but can't get to grips with it and am still stuck with EAGLE.

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2024, 09:42:52 pm
content: Quote from: KungFuJosh on July 07, 2024, 09:32:51 pmBetter.Would you consider shifting thosethat can beto above their respective devices and making them larger still ?

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 09:58:20 pm
content: Quote from: Martin72 on July 07, 2024, 09:40:13 pmThe short answer is: laziness and impatience combined with the lack of evidence showing that it's needed.I might be convinced to add them all, but I don't like the extra time it takes to single everything out (while testing), especially when any difference is negligible. Look at my updated reading above based on Mike's feedback to match the test voltages. The ST42 with a direct connection to the DUT, and the ST2832 using the non-isolated kelvin connections had excellent matching, and that kelvin connection is one of the longest in the section.Quote from: Martin72 on July 07, 2024, 09:40:13 pmThank you, KiCad us great. I learned it out of necessity. Years ago I was using some crappy proprietary PCB designer (PCBExpress), and refused to pay the cuckoo prices for Eagle when I outgrew that other one. Like anything though, it's easier to learn if you're not stubborn about whatever program you were previously used to. 😉 There are tons of youtube videos to help learn it also. Also some good plugins too.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 10:02:10 pm
content: Quote from: tautech on July 07, 2024, 09:42:52 pmI don't like inconsistencies like that. Use one of your 500 pairs of reading glasses. 😉😉

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2024, 10:08:03 pm
content: Quote from: KungFuJosh on July 07, 2024, 10:02:10 pmPCB finished size ?

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 07, 2024, 10:24:21 pm
content: Quote from: tautech on July 07, 2024, 10:08:03 pm150mm x 120mm, not too small.

author: Martin72
author_rank: Super Contributor
timestamp: July 07, 2024, 10:33:17 pm
content: That leaves the vexed question of calibration....I see several possibilities.The first option is to send in the assembled board and have it measured.Second possibility:Those of us who are "blessed" with an LCR bridge that has 0.05% basic accuracy and is therefore well below the component tolerances, use their device as a reference - But would also have to have it calibrated first to be on the safe side.Then, of course, there is the third option:You don't care, the main thing is that you have something to measure.

author: mawyatt
author_rank: Super Contributor
timestamp: July 08, 2024, 12:50:26 pm
content: If the PCB can fit inside those small USPS boxes that ship for ~$5 anywhere in US, you could have folks around the country make measurements with different meters for comparisons, kinda like folks do with the Voltage Source Cal group.Also consider a thermistor on the PCB.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 08, 2024, 02:12:41 pm
content: Quote from: mawyatt on July 08, 2024, 12:50:26 pmIt should definitely fit in the small flat rate priority box which is ~$8 to ship anywhere in the US.I've never used a thermistor before. What type should I get, and how should I set it up? ...and is it really better than measuring ambient temperature?Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 08, 2024, 03:29:24 pm
content: Wow that flat rate has gone up since last we used!!Thermistors are used to measure temperature of the thermistor element, and are usually inexpensive (<$1) and most folks have a DMM that can use them. If the thermistor is mounted to your PCB then the readings should give a rough indication of the PCB temperature.Best to study up on thermistors (lots of on-line tutorials) as there are an almost infinite variety of such!!Thermistors are non-linear and most DMMs use Steinhart-Hart equation:1/T = A + B(lnR) +C(lnR)^3, where T is Kelvin and A, B and C are Thermistor Parameters.Common types are NTC 10K and 5K @ 25C.Here's an example SMD from TDK.https://www.digikey.com/en/products/detail/tdk-corporation/NTCG163JF103FT1/614632Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 08, 2024, 03:44:37 pm
content: Quote from: mawyatt on July 08, 2024, 03:29:24 pmThank you, that's what I needed. I understand the (very) basics of thermistors, but there's a wide range of accuracy, value, etc. I didn't want to guess at what specs would be acceptable.I don't want to use anything smaller than 0805, I assume this should be fine?:https://www.mouser.com/ProductDetail/594-NTCS0805E3103FLTShould I use the same connection setup as the other solo items?Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 08, 2024, 03:59:05 pm
content: Suspect that should work with most DMMs. Since the expected PCB temperature should be 25C +-5C this should give a reasonable indication of PCB temperature.Of course humidity also becomes a factor, but that's another level to consider as you dive down the Rabbit Hole of Precise MeasurementsEdit: Should have mentioned no need for 4 wire measurements to Thermistor, 2 wire measurement should be fine.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 08, 2024, 07:27:36 pm
content: I'm changing the 1mF to 2824 (was 2812). That way people can choose between either 10% at 6.3V or 20% at 10V. The old one was 6.3V 20%.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 08, 2024, 10:55:54 pm
content: Assuming no glaring issues, this may be the final version of the V5 board. Feedback is always welcome.I also attached 2 BOMs. One for Mouser, and one for JLC PCBA service. Most of the JLC parts seem fine, a few I'm not sure about (haven't heard of a couple brands before). They also didn't seem to state the value for their thermistor. I might mix and match parts from both sources, or skip the PCBA.ETA: After seeing what it would cost to preorder parts for PCBA, I will not be using that service. Yikes.Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: July 09, 2024, 01:30:21 pm
content: Just noted, don't forget holes in the corners for nylon standoffs.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2024, 01:51:00 pm
content: Quote from: mawyatt on July 09, 2024, 01:30:21 pmFiiiiiiiiiiiine. 😉Is 3.5mm good for you?

author: Martin72
author_rank: Super Contributor
timestamp: July 09, 2024, 02:48:22 pm
content: Quote from: KungFuJosh on July 06, 2024, 07:08:54 pmThey will then sit loosely in it, but yes, 1.5mm is also possible.Data sheet/origin is at work, I won't get to it for another 2 weeks.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 09, 2024, 03:34:29 pm
content: I noticed an issue with my dissipation factor test results. For some reason when I ordered the parts for V4, I substituted the 50Ω with a 47Ω and the 160kΩ with a 158kΩ. Those two test results were lower than they were supposed to be, which is not surprising.I corrected those values on the Mouser BOM, and here's the project link:https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=6851743830All parts come out to less than $30, which is nice. Unless you want test pins, and then it will cost twice as much. 😉😉The 1mF cap is backordered until August, but I'm guessing that won't matter.Here's (hopefully) the final V5 board version:Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 10, 2024, 02:31:35 pm
content: I ordered the new PCBs and parts. I should be able to make a new board next week. I ordered some extra PCBs in case anybody in the US wants one.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 16, 2024, 06:57:48 pm
content: I got the PCBs in. Now I just need to throw some stuff on there.

author: Martin72
author_rank: Super Contributor
timestamp: July 16, 2024, 07:22:19 pm
content: That went very quickly

author: mawyatt
author_rank: Super Contributor
timestamp: July 16, 2024, 08:44:44 pm
content: PCBs look niceCheck out the repeatability of those Short and Open Calibrations spots. Do a Short and Open Cal after everything is stable, then make Short and Open readings at various frequencies, record, then disconnect/reconnect and repeat, then swap Kelvin Leads (Red and Black), do again.This should give a good indication of how well your Short and Open Cals are behaving.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 16, 2024, 09:21:12 pm
content: Quote from: mawyatt on July 16, 2024, 08:44:44 pmThanks!I'm too lazy for that. I'll just send you a PCB and you can let me know. 😉

author: Martin72
author_rank: Super Contributor
timestamp: July 16, 2024, 09:24:36 pm
content: How many of them do you have?

author: mawyatt
author_rank: Super Contributor
timestamp: July 16, 2024, 09:32:18 pm
content: Quote from: KungFuJosh on July 16, 2024, 09:21:12 pmOk will do. If you want we'll populate the PCB and record the measurements, then return to you for your verification measurements.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 16, 2024, 10:51:08 pm
content: Quote from: mawyatt on July 16, 2024, 09:32:18 pmI already populated one, but I can send it to you along with an unpopulated PCB for you to keep, and you can ship mine back after testing if that works for you.I'll hopefully have time to run through the tests in the next day or two.Quote from: Martin72 on July 16, 2024, 09:24:36 pmI might have ordered 20. 😉Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: July 17, 2024, 07:47:26 pm
content: I placed an order with Mouser earlier - what was the thermistor good for again?I forgot to order it earlier...

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 17, 2024, 07:53:25 pm
content: Quote from: Martin72 on July 17, 2024, 07:47:26 pmThe thermistor was to make Mike happy. 😉😉...but I guess also to test the temperature of the PCB.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 17, 2024, 08:52:56 pm
content: Here's the results comparing my ST2832 and ST42 on V5 of the test board. Most tests were matched at 360mVrms (ST42 tested at about 358mVrms).The DC bias values are based on 1kHz or 10kHz frequency for AC. It matters for some reason. 🤷I think I did step DF test at 1Vrms. I forget, that was way back to yesterday.Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: July 17, 2024, 09:13:38 pm
content: Interesting results.It is also easy to see how the reactive part of the resistance increases at higher frequencies, as a result of the ever decreasing real value.Or how at higher frequencies (100, 200kHz) the accuracy decreases (up to 4%).I want to reproduce this as soon as possible.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 17, 2024, 10:10:59 pm
content: Quote from: Martin72 on July 17, 2024, 09:13:38 pmYou'll hopefully receive your PCB next week or the week after. Mike should have his (and my tested board) on Saturday.

author: mawyatt
author_rank: Super Contributor
timestamp: July 18, 2024, 12:38:50 am
content: Quote from: KungFuJosh on July 17, 2024, 08:52:56 pmUse your SDM3065X to measure the Thermisistor (2 wire), it should yield ~78F or ~25.6C.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 18, 2024, 03:32:48 am
content: Quote from: mawyatt on July 18, 2024, 12:38:50 amOops. A little late now, it's on the way to you. I'll try it out next time. 😉

author: mawyatt
author_rank: Super Contributor
timestamp: July 18, 2024, 12:35:59 pm
content: No problem, we'll measure it when the PCB arrives!!Best,

author: Martin72
author_rank: Super Contributor
timestamp: July 22, 2024, 09:58:05 pm
content: Quote from: KungFuJosh on July 17, 2024, 10:10:59 pmIt's not ready yet, but Mouser delivered today and everything has arrived.I ordered everything from your parts list 2 times, you never know how stupid you can be when soldering.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 22, 2024, 10:30:01 pm
content: Quote from: Martin72 on July 22, 2024, 09:58:05 pmI always get at least 3 for the same reason...except even stupider: sometimes I don't pay enough attention when I test SMT stuff, and the parts might become airborne. 🤣 ...only lost 2 or 3 items on the last board I made.

author: mawyatt
author_rank: Super Contributor
timestamp: July 23, 2024, 03:08:24 pm
content: PCB received, and testing underway. PCB looks niceSee overhear for some discussions on LCR sensitive measurements.https://www.eevblog.com/forum/testgear/sensitive-lcr-meter-measurements/Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 23, 2024, 07:32:14 pm
content: Man, I want one of those Hioki LCR meters. Gimme that 8MHz! 😉

author: mawyatt
author_rank: Super Contributor
timestamp: July 24, 2024, 12:17:52 am
content: They are good, real good in every way (except fan noise). Why we have oneThey operate differently than most tho, and takes awhile to get used to.Instead on bashing the operation we spent time learning to use it, and discovered that the way it works is to maximize measurement accuracy and speed. When you get to doing lots of measurements, you begin to appreciate the thought that went into this fine instrument, and really like the ability to select 4 parameters for display and easily change each without fiddling thru a bunch of menus. In general you don't need to navigate a bunch of menus, most things you want to do are just one touch away.Now that we've become somewhat proficient in use, it's value has increasedHowever, the fan noise is horrificBest,

author: mawyatt
author_rank: Super Contributor
timestamp: July 24, 2024, 05:21:36 pm
content: Should add that the IM3536 can deliver 5VRMS max and 0.1ARMS max, both verified by DMM and DSO, of course not simultaneously and over certain frequency rangesBest,

author: Martin72
author_rank: Super Contributor
timestamp: July 24, 2024, 10:07:35 pm
content: Yes, I've also had my eye on your Hioki.But when the time comes, I'll opt for an LCX100 from R&S.

author: mawyatt
author_rank: Super Contributor
timestamp: July 25, 2024, 02:16:51 am
content: We looked at R&S, Keysight, Tonghui and Instek, but decided on the Hioki IM3536 based upon what we needed and the $ value. Only serious issue was with the lack of internal graphing display capability, we solved that by creating our own custom RPi/PC resident plotting routines which have served well.Of course YMMV,Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 25, 2024, 03:38:48 pm
content: The LCX100 might be comparable cash value if it can beimprovedthe fun way.

author: Martin72
author_rank: Super Contributor
timestamp: July 25, 2024, 09:20:18 pm
content: QuoteThe LCX has this feature (optional), but whether this is “fun” given the screen size is another question.In contrast to the Hioki and R&S, the ET35 has a “huge” 7” screen - but only displays numbers on it....But we digress.

author: mawyatt
author_rank: Super Contributor
timestamp: July 26, 2024, 02:40:23 am
content: Quote from: Martin72 on July 25, 2024, 09:20:18 pmMaybe someone can conjure up some code for the display on the ET35Best,

author: Martin72
author_rank: Super Contributor
timestamp: July 29, 2024, 05:42:03 pm
content: Look what the post has brought...I have most of the components, now it's time to solder - and then measure...

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 29, 2024, 06:25:20 pm
content: Quote from: Martin72 on July 29, 2024, 05:42:03 pmNice! Are you going to use the terminal pins? I'm curious how that works out if you do.

author: Martin72
author_rank: Super Contributor
timestamp: July 29, 2024, 06:53:57 pm
content: You've left enough space for me to have both options open, so yes, it will be fitted and I'm curious to see if there are any differences later on.

author: Martin72
author_rank: Super Contributor
timestamp: July 30, 2024, 09:43:00 pm
content: I had soldered the coils on at work today, then quickly measured them with the calibrated ST2830.The results were rather mixed, especially with the smaller values.At home, a quick check with the ST42 was the same.I've just got the datasheets available, which show the frequencies used to determine the values.10nH 450Mhz100nH 25Mhz1µH 10Mhz10µH 2Mhz100µH 1MhzAnd always with an SMD test fixture and either a network or impedance analyzer.We are miles away from that with our LCR meters.I would leave out the 10nH and 100nH and, if possible, not select any HF components for the values above 1µH.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 30, 2024, 10:40:30 pm
content: I'll try finding parts that used lower frequencies to test. At least under, let's a pick a random number, and say 5MHz. 😉

author: mawyatt
author_rank: Super Contributor
timestamp: July 30, 2024, 11:02:19 pm
content: Small inductances at low frequencies will be very difficult to get reliable and repeatable results, reason is impedance Z is j*omega*L, where omega is 2*pi*F. So 10nH at 100KHz is only ~6.3 milliohms Z, at 1MHz a little better at ~63 milliohms and at 5MHz ~0.314 ohms.For an instrument with 100KHz limit, seems 0.1 or 1uH is a reasonable lower limit with a Z of 0.0628 or 0.628 ohms respectively, which should be measured with some fidelity with a quality LCR meter.One must remember that the LCR meter doesn't directly measure Inductance (or Capacitance for that matter), it measures the voltage across and the current thru the DUT, then computes the impedance Z at frequency, then the equivalent Inductance (or Capacitance) to produce that impedance.With low impedances the setup and fixture as well as DUT contact impedance play a significant roll in the readings, the meter's Short Calibration attempts to remove these parasitic series impedance effects, but never quite prefect. Such a low DUT Z, the meter will supply a large current (usually the larger the better) to produce a higher DUT voltage reading, but limits come into play, especially with battery powered Handhelds (Tweezers).Likewise high DUT impedances can be troublesome, such as small capacitances. Here parasitic shunt capacitances becomes the culprit and the meter attempts to remove this effect with an Open Calibration, effective but never perfect. Operating with a higher voltage and frequency increases the DUT current which helps but meter limits also come into play, usually favoring bench types over Handhelds (Tweezers).Kelvin Clips just complicates things with the long cables, which can influence readings, favoring lower frequencies, and why direct connected DUT fixtures are generally preferred for both low and high Z components at moderate to higher frequencies.Anyway, the trials and tribulations one goes thru for accurate repeatable DUT measurements with LCR Meters (any meters for that matter). As can be seen one Meter does not serve all DUTs, why we have the TH2830, IM3536, DER-5000 and 3 VNAsNot to mention the various DUT fixtures, both OEM type and DIY including modded OEM types, all for the sake of mostly passive component measurements, of course YMMVBest,

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 30, 2024, 11:29:13 pm
content: I wish I looked at the test frequencies before making the BOM.It looks like 450MHz is pretty common for testing 10nH, so I'll just skip that.However, it looks like there are some options for 100nH at 100kHz. For example: FP0805R1-R10-R.

author: Martin72
author_rank: Super Contributor
timestamp: July 30, 2024, 11:44:21 pm
content: @mawyatt:It is exactly as you write it and I really hope that the people who are interested in it are aware that in the end only current and voltage are measured.For example, we manufacture most of the required chokes/transformers ourselves.They are not only measured but also calibrated (air gap).This is solved in various ways, not only or rather rarely with a “simple” measurement with an LCR.Mostly by means of a resonant circuit or with the voltage-time surface method, where real current can then flow (measuring an output filter choke with a few µ...mA makes almost no sense, so it is better to send a pulse with a rated current of up to 200A through the choke).If a test board is now developed, as here, which is intended for normal LCR measuring bridges in the affordable range, then the references on the board must first be measurable with such devices.If it is only about the pure L-value, things like the quality Q or the RDC hardly play a role.And since the measuring current is small anyway, the core can also be “crap”, you won't reach saturation anyway.

author: Martin72
author_rank: Super Contributor
timestamp: July 30, 2024, 11:57:14 pm
content: I ordered the components from Mouser according to your BOM.And Mouser has a datasheet for each component, which also shows how the values were determined.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 31, 2024, 12:04:28 am
content: Quote from: Martin72 on July 30, 2024, 11:57:14 pmI checked the datasheets on Mouser, up to 1uF and they didn't show any test frequencies. The inductors were easy to find.

author: Martin72
author_rank: Super Contributor
timestamp: July 31, 2024, 12:09:07 am
content: I was only referring to the inductors.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 31, 2024, 12:14:46 am
content: Quote from: Martin72 on July 31, 2024, 12:09:07 amDamn it. My brain did the dumb thing where I occasionally swap the H and F when looking at crap too quickly. 🙄

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 25, 2024, 08:49:37 pm
content: Here's a comparison test I just finished today. Included is my ST2832, and my Hioki IM3570, as well as Mike's TH2830 and Hioki IM3536.Tests were done using the guard connection tied to a shield plate under my soldering mat. I used the Hioki fixture with the Hioki, and the TH/ST fixture with the TH/ST LCR. The meters were warmed up for a minimum of 90 minutes before starting the tests.This was the basic setup:If all goes well, I might be able to add the Hioki 3532-50 to this later this week.Once I've done that, I'll be replacing some of the inductors on the board with better test frequencies than what I originally chose. If that goes well, I'll update the BOM on Mouser.Thanks,Josh

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 26, 2024, 07:22:44 am
content: This is the most stable and consistent overview of LCR-measurements I have ever seen, it seems the Penguin is doing its job very well!Do you have any idea why Mikes instruments measure around 97uF compared to 88uF at your equipment at the 1kHz Capacitance measurement? And why is the dissipation factor at Mikes TH2830 that high? (936.3)Anyhow, many thanks for sharing this design and the tables. Most parts show stunning consistency and deviations of that amplitude and especially of that rate are to be expected - especially at the first measurement runs.By the way, does the Test PCB have a GND-plane you could connect to "Guard"? Would that be a good idea?

author: mawyatt
author_rank: Super Contributor
timestamp: August 26, 2024, 12:41:37 pm
content: Don't put much faith in respectable ceramic capacitor measurements, except C0G/NP0 types. The popular high "K" X5R and X7R ceramic caps are notorious for all sorts of ill effects, from Voltage, Temperature, Time, Hysteresis and so on. Just soldering a X7R or X5R SMD cap can change the measured value considerably!!However, just the opposite for the C0G/NP0 ceramic types, they are generally outstanding in performance and stability, but with a much lower effective dielectric constant than X5R or X7R have less volumetric efficiency.BTW we've found that polarized Tantalum capacitors generally have better overall performance than high "K" dielectric ceramic types, however are more expensive and somewhat limited availability.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 01:41:13 pm
content: Quote from: Phil1977 on August 26, 2024, 07:22:44 amThank you!Quote from: Phil1977 on August 26, 2024, 07:22:44 amOh, yes. You see, if you do the math, it's clear that Murphy's Law applies. It should have said 0.3325. 😉 Corrected sheet attached. Any other errors/typos? It was a lot of data entry, I'll be happy if that was the only one.As Mike said, I think those X7R capacitors are more sensitive to environmental conditions. If I get the 3532-50 going this week, I'm looking forward to seeing how that compares. I'll see if I can get the PCB / thermistor to a specific temperature before I test. 🤔Quote from: Phil1977 on August 26, 2024, 07:22:44 amNo ground plane on the board. I suspect it wouldn't be ideal given that the kelvin probes would have to pass through the ground plane. Using an external shield (as pictured) keeps everything covered.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 01:55:53 pm
content: Quote from: mawyatt on August 26, 2024, 12:41:37 pmYeah, I wish they made those larger values in C0G/NP0. I'm guessing there's a reason they don't.The 100µF is tantalum:F951A107KAAAQ2KYOCERA AVXTantalum Capacitors - Solid SMD 10V 100uF 1207 ESR=1 Ohms 10%Is polarization that important? There are afew options at mouserfor an alternative if you think that specific capacitor was a poor choice.Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: August 26, 2024, 02:22:06 pm
content: Kyocera/AVX is a well respected component OEM. Polarized Tantalums are fine from our experience, just pay attention to the polarization like with an Aluminum Electrolytic or Polymer, altho Tantalums seem more susceptible to over-voltage.One reason Tantalums aren't as popular now is the cost relative to Ceramics or Electrolytic/Polymers types.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 03:01:54 pm
content: I picked it because of the brand. Do you think I should replace it with a polarized cap? I don't see why polarization would help here in a non-polarized test?

author: mawyatt
author_rank: Super Contributor
timestamp: August 26, 2024, 03:15:32 pm
content: Don't think it really matters, you are using the Cap as a reference device. Generally LCR Meters won't push much voltage across a high value DUT Cap, and even tho the AC does slightly reverse bias the polarized DUT Cap, this usually is small enough not to matter.We've often used Polarized Tantalums and Electrolytic Caps where the AC component can slightly reverse bias the capacitor with no ill effects. In fact, 1/2 a century ago we utilized a wet-slug tantalum as the input coupling for an ultra low noise, low impedance source where the input was bipolar without issue and this went into full production.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 04:26:55 pm
content: The largest environmental factor seems to be the humidity. You were around 40%, while I was typically around 58%.Would that make such a big difference for cap value there?

author: mawyatt
author_rank: Super Contributor
timestamp: August 26, 2024, 04:41:41 pm
content: Shouldn't matter that much for this high cap value, since relative Z is very low.Check the Venkel C0G SMD caps we sent with your IM3570 and SMD Fixture.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 08:55:59 pm
content: Quote from: mawyatt on August 26, 2024, 04:41:41 pmMy SMT fixture correction is tricky. This is what I got for the 1pF:In your email, you had the 1pF at:I don't know anything about Q measurements, but that's certainly not close to yours.Never mind. I just noticed my LCR was still on 5MHz. 🙄Here it is at 100kHz:

author: Martin72
author_rank: Super Contributor
timestamp: August 26, 2024, 09:28:49 pm
content: Which 1pF capacitor is it ?

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 09:42:17 pm
content: Quote from: Martin72 on August 26, 2024, 09:28:49 pmMike supplied them (thanks Mike!). He said: "Special Hand Selected Ultra-Stable High Q C0G/NP0 Venkel 0805 SMD Chip Caps, 1pF, 10pF, 100pF and 1000pF"Here's the rest of them. There's 3 for the 100pF since the Q factor kept rising until it was out of range. Apparently it stops counting at 10k.I don't know why one cap's Q would be super high, while another went negative. I don't understand Q (slightly better after googling, but still, meh), but that seems odd to me. 🤷

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 09:56:36 pm
content: I did a dumb experiment and ran correction for the Hioki kelvin clips and just held them against the SMT caps (guard on too). I'd say it did okay for testing SMT caps that way. 🤣I didn't bother with the 1pF, correcting for that range would be a lot trickier.

author: Martin72
author_rank: Super Contributor
timestamp: August 26, 2024, 10:01:15 pm
content: Put simply, the quality factor Q indicates how “pure” the reactance is.This can be seen from the definition Q=X/R or even better, because in this case a capacitance, by Q=1/D.The lower the dissipation factor, the higher the quality Q.I'll think about why you had a negative Q in one case tomorrow, it's late for that now.But maybe Mike will have been quicker by then.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 10:13:03 pm
content: I would guess the Q factor was off because of this fixture and/or the user. 😉Considering that Mike got between ~1800 to ~3000, and I at least got a positive number with the kelvin clips, it's probablymostlythe cheapo fixture.

author: Martin72
author_rank: Super Contributor
timestamp: August 26, 2024, 10:20:31 pm
content: Measure it again and then with the impedance as 2nd value.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 11:09:50 pm
content: I think it was mediocre corrections. I ran the corrections again with the SMT fixture, then tested all 4 again. Q on 1000pF shot up to above 10k, then eventually settled ~5476.I figured out a dumb trick to get a better open correction. I stuck a hex key between the spring lever arm and the stop post, and it was about the right thickness. 😉

author: mawyatt
author_rank: Super Contributor
timestamp: August 26, 2024, 11:20:30 pm
content: Q is define as X/R , and is alway positive.Z is the DUT Impedance Magnitude at angle, with R = Z*Cos angle and X is Z*Sin angle.So Q is equal to Sin angle/Cos angle, and should be considered as the absolute value of such.If you can display 4 measurement parameters like Hioki, we always show the DUT Impedance Angle as this gives a lot of information on the DUT characteristics and measurement.With high Q Capacitors like the C0G types, the Impedance angle is around -90 degrees and highly sensitive to the "Short Calibration", setup, fixture and so on. We don't place much value in Q measurements above ~ a few hundred as being reliable or repeatable.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 11:29:17 pm
content: Okay, here they are with all the fun info. 😉It's interesting how much of an effect the placement of the DUT in the fixture has on Q. The 1000pF cap is fine when seated against the back wall of the plastic V, but the Q goes out of range when it leans forward on the front wall. The other meter values didn't care too much.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2024, 11:31:43 pm
content: The inconsistencies and the nuisance of using SMT stuff in this fixture makes me want the HIOKI L2001 tweezers. Now I just need a silly good deal on them. 😬OTOH, I measured all 4 with the ST42 in less time than it takes me to get one capacitor into position on the SMT fixture.

author: mawyatt
author_rank: Super Contributor
timestamp: August 27, 2024, 12:22:33 am
content: That ST42 is indeed impressiveBTW note how as the angle approaches -90 the Q gets sorta wild, wouldn't put faith in those really high "Q" values.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 27, 2024, 12:36:07 am
content: Quote from: mawyatt on August 27, 2024, 12:22:33 amI've never needed to put this much thought into capacitor selection, but it is fun to learn about. So for edumacational porpoises:If you don't trust the Q value, do you try running corrections again and/or checking how well the DUT is sitting in the fixture? If that doesn't change anything, what then?

author: mawyatt
author_rank: Super Contributor
timestamp: August 27, 2024, 01:13:15 am
content: For these low value capacitors we are more concerned with the Capacitance C than Q and with the overall impedance Z.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 27, 2024, 01:29:57 am
content: Quote from: mawyatt on August 27, 2024, 01:13:15 amSo at what point do you start caring about Q?

author: mawyatt
author_rank: Super Contributor
timestamp: August 27, 2024, 12:44:52 pm
content: We generally don't, for us "Q" is just a qualitative term like High Q or Low Q, similar to "Low Loss".For example the mentioned High "Q" C0G type capacitors, here we are interested in the capacitance but knowing it's "Low Loss" because of High "Q", meaning Rs is low compared to Z.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 27, 2024, 01:42:52 pm
content: Quote from: mawyatt on August 27, 2024, 12:44:52 pmPerfect, now I just need to remember that. 😉

author: Martin72
author_rank: Super Contributor
timestamp: August 27, 2024, 08:41:41 pm
content: Q is not entirely uninteresting.Chokes, for example, which have the same induction value at first glance, but differ significantly in terms of Q, will subsequently cause problems in terms of losses/function.The same also largely applies to capacitors.What is interesting in this context is how precisely the meters display or calculate and indicate this value.

author: Kean
author_rank: Unknown
timestamp: August 28, 2024, 04:32:05 pm
content: Did the Gerber files for V5 get shared?I'd like to make one of these up at some point to see how my CKT5000 compares with my handheld Tonghui and ST42 tweezers. And whatever I buy next....

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 28, 2024, 04:41:29 pm
content: Quote from: Kean on August 28, 2024, 04:32:05 pmNot yet. I'm waiting on updating the BOM and stuff. For now I have extra (unpopulated) PCBs I can sell for $10 plus shipping if anybody wants them.

author: Kean
author_rank: Unknown
timestamp: August 28, 2024, 04:57:25 pm
content: Thanks Josh. I can wait. Just wanted to be sure I didn't miss a mention of it.I haven't ordered the parts yet, and shipping a single PCB to me down under makes little sense.

author: mawyatt
author_rank: Super Contributor
timestamp: September 04, 2024, 01:22:53 pm
content: Here's something folks might find interesting wrt to DMM testing/calibration and forgoes the Kelvin Clips.https://www.eevblog.com/forum/testgear/ac-rms-dmm-tests/msg3940957/#msg3940957We may have posted something on the Resistive & Capacitive devices but can't remember since long agoObviously these are specific to Bench type DMM use with the 4 terminals (except the Capacitor set which is just 2 terminal).Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 05, 2024, 11:04:25 pm
content: I got the Hioki 3532-50 working, and ran it through the Cal Test PCB.Looks decent, but could definitely use a calibration/adjustment from Hioki. PDF attached.

author: shabaz
author_rank: Frequent Contributor
timestamp: September 06, 2024, 12:17:25 am
content: Nice instrument. I've not used a Hioki LCR meter.I had a quick look at the PDF, the results look like it's functioning well. Unless I missed something, aside from the very large inductances at high frequency, which might not be very relevant, all remainder measurements looks very close to the comparison measurements, at least so close that any circuit designed for normal tolerances should function extremely well if components are selected based on measurements from the Hioki.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 06, 2024, 12:37:51 am
content: Quote from: shabaz on September 06, 2024, 12:17:25 amThanks, I'm a big fun of Hioki LCRs. The quality is unmatched so far from what I've used.There are two Hiokis on there (of mine, and the 3rd one is Mike's) all are really nice.Regarding the 3532-50, for the most part it agrees pretty well. However, there are a few things that are too far off.For example, 1M and 10M resistance measurements are generally bad. 100k is also too far out to be acceptable, though not nearly as bad. 10kΩ and below generally seem close enough.Step dissipation factor is not good enough either, especially in the smaller values.Capacitance is generally pretty good except for 10pF at 10kHz and below. Granted, that's not really expected to do very well, but was father off than the other meters.Inductance in general is pretty good except for 100nH is way off. However, I don't think those inductors were anywhere near where they should have been for specified test frequencies. That said, it was still farther off than any of the other meters. I have new caps and inductors to try out on a new board now that all these meters have been compared.Still generally pretty darn good for a 23 year old LCR meter. Hioki does adjustments with no extra charge when they do calibrations for Hioki gear, so I'm waiting to hear back from them for pricing.Thanks,Josh

author: shabaz
author_rank: Frequent Contributor
timestamp: September 06, 2024, 12:53:42 am
content: I've got an ancient LCR meter that I need to work on, (it's been on the back-burner for a couple of years!) it runs, but there's a higher discrepancy than desired, compared to a more modern LCR meter.It's a 'Chen Hwa 1061 LCZ meter'. It was low-cost so I took a gamble. When I took a look inside, it was pretty old.. running with a Zilog Z80.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 06, 2024, 01:43:17 am
content: Quote from: shabaz on September 06, 2024, 12:53:42 amThat's an old school beast! The picture I found made it look kinda huge. It should be a fun project though when you finally have time.

author: shabaz
author_rank: Frequent Contributor
timestamp: September 06, 2024, 02:04:31 am
content: Definitely. I'll take some pics and share them next time I have it open.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 07, 2024, 11:32:23 pm
content: Here's the Gerbers andBOMfor the LCR Cal Test V5 PCB.Note: This is being shared for home & hobby use. Commercial use or reproduction is not approved. Use at your own risk; I take no responsibility for anything.There are details in the PDF version of the BOM. For example, I used different caps for the 1nF whether testing capacitance or step D factor. The cap listed for step D factor had values in the range needed to be close to the nominal targets.Also note that there are 2 inductors listed for 100µH. The one marked NRND is easier for most people to measure if they don't have an LCR that supports higher frequencies. I guess grab them while they last. 😉Thanks,JoshPS. If anybody in the US would like, I do have a few unpopulated PCBs available for $10 each plus shipping. Send me a PM if interested.

author: Martin72
author_rank: Super Contributor
timestamp: September 07, 2024, 11:48:44 pm
content: That reminds me that I should finish assembling my circuit board.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 08, 2024, 12:03:38 am
content: You might want to get at least the replacement inductors from the updated BOM.I improved the 1nF and lower cap choices too, but the previous ones were probably fine.Unrelated side note: Mouser sent me the wrong inductors for the 100nH range. They were 100µH instead of 100nH. I'm waiting on replacements for those, but the rest were great. I'll eventually posts some measurements when I'm done screwing around with other things. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 10, 2024, 12:36:52 am
content: Mouser sent me the wrong value for 100nH, but surprisingly, the 805 chip book I bought had some 10nH and 100nH I didn't have any trouble testing. 🤷Here they are in the SMT test fixture. I have to redo the kelvin tests with the cable correction done. Oops.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 10, 2024, 01:02:36 am
content: Here they are with the test PCB. These values are very sensitive with the kelvin clips.

author: Martin72
author_rank: Super Contributor
timestamp: September 10, 2024, 05:33:49 pm
content: Quote from: KungFuJosh on September 05, 2024, 11:04:25 pmEspecially in the resistance range, it looks as if something high-impedance is lying parallel in the measuring path.Possibly check the front end.

author: mawyatt
author_rank: Super Contributor
timestamp: September 10, 2024, 06:06:05 pm
content: Quote from: KungFuJosh on September 10, 2024, 01:02:36 amTry usingLow Z ONif possible, unless worried about DUT damage with high current. This provides more DUT current with low Z components and thus creates a higher measurement voltage which improves measurementsYou need to do a Cal with it ON as well.BTW think your previous post should be 100nH and 10nH, not nF!!Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 10, 2024, 07:37:32 pm
content: Quote from: mawyatt on September 10, 2024, 06:06:05 pmI will give that a try, thank you.QuoteI switch those around so frequently it's ridiculous. I usually catch them and edit before anybody notices though. 😉Quote from: Martin72 on September 10, 2024, 05:33:49 pmInteresting point.I'm not in a rush to open it back up, but I'll probably need to check that out. I didn't see anything astray when I cleaned it (gently) before closing it up. If only I could get a schematic for it. 🙄ETA: I thought about it more, and that doesn't make sense to me. Every measurement range is separated by resistance level. 1M and 10MΩ are separate levels (you can hear the relays click as it switches through the different ranges from .1Ω to 100MΩ), and I can't think of any single thing in the front end that would throw them both off by ~50%. If a 10M resistor found its way there, that would make sense in the 10M range, but the 1M range shouldn't drop lower than 90%.Is there anything besides needing adjustment that would set two separate ranges apart? Or maybe the resistance ranges are in series? If that's the case, then there would need to be something around the 1MΩ position to throw off only the higher ranges. I should test the 100MΩ range and see what that looks like. I still don't know what could throw both ranges off by ~50%.My hope is that those ranges only need adjustment. What do you think?Thanks,Josh

author: mawyatt
author_rank: Super Contributor
timestamp: September 10, 2024, 11:45:28 pm
content: Could this be the Cal values got messed up for the Resistance Ranges?Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 11, 2024, 12:22:05 am
content: Quote from: mawyatt on September 10, 2024, 11:45:28 pmThat's my theory. 100k is slightly off, and 1M and 100M are at 50%. I don't know what would have messed them up. The device is 23 years old, it's time for an adjustment. If I can figure out how. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 11, 2024, 12:48:27 am
content: My old version (I think V1) of the Cal Test PCB went up to 1GΩ so I was able to test 100MΩ on there. It shows about ~80MΩ, so 20% less than the nominal value. Whether it's actually off or not, I don't know, but it does tell us that only the 1M and 10M ranges are goofy.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 11, 2024, 01:13:02 am
content: Looks like the 100M range is probably ok on the 3532-50. At 1kHz, the IM3570 is reasonably close.At 5Hz the IM3570 reads it verry niiiice.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 13, 2024, 08:54:48 pm
content: Quote from: KungFuJosh on September 07, 2024, 11:32:23 pmBOM updated again. Mouser incorrectly had 100nH listed on what was actually a 100µH inductor. This is why I always test all parts, no matter where they come from.

author: Kean
author_rank: Unknown
timestamp: September 14, 2024, 11:13:38 am
content: Quote from: KungFuJosh on September 13, 2024, 08:54:48 pmFor those playing along...The wrong part is Murata LQM21DN101M70L - listed as 100 nH, but actually 100 uH (I've reported the error on website)The replacement is TDK TMS201610ALM-R10MTAA - confirmed as 100nH on datasheet. It is 2016 metric so 0806 rather than 0805 - close enough.I haven't ordered the parts or PCBs yet, but probably will next week.If anyone else in Australia wants one, I may have some PCBs and parts available. I probably won't buy multiples of all parts, as it works out about AUD $50 per set.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 16, 2024, 05:58:02 pm
content: Quote from: Kean on September 14, 2024, 11:13:38 amFor the cheap stuff, get multiples, especially the 0805 stuff. I find at least 1 or 2 0805 goes flying across the room per project. 🤣

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 16, 2024, 06:44:53 pm
content: I got the replacement 100nH in today, and it looks good.

author: watchmaker
author_rank: Unknown
timestamp: October 04, 2024, 09:09:03 pm
content: Thanks for the board Josh. Just ordered the parts; both Mouser and Digikey are backordered on the 10v 1000uF Tant.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 04, 2024, 11:41:34 pm
content: Quote from: watchmaker on October 04, 2024, 09:09:03 pmYou're welcome!I added an alternate 1000uF cap to the BOM, see if you can get them to add it to your order, or swap them out.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 10, 2024, 01:59:40 pm
content: For anybody curious about the Step D Factor test results, here's what to expect with the Panasonic resistors in the BOM:Measured cap + standard values:29Ω = 0.00018 (cap only YMMV - test your cap and adjust the rest)79Ω = 0.00049 (29Ω + 50Ω)162Ω = 0.00101 (29Ω + 133Ω)797Ω = 0.00506 (29Ω + 768Ω)1609Ω = 0.01010 (29Ω + 1.58k)16029Ω = 0.10071 (29Ω + 16k)160029Ω = 1.00530 (29Ω + 160k)

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 12, 2024, 02:43:57 pm
content: For anybody else wondering:Wah inductors are for Wah Wah guitar pedals. Typically 500mH to 700mH. You can google "Wah Inductor," or look for "Red Fasel inductor" if you want to populate that.Thanks,Josh

author: watchmaker
author_rank: Unknown
timestamp: October 12, 2024, 07:41:07 pm
content: OK Josh, I am ready to populate your board.My first attempt at SMDs. Thankfully I am used to screws smaller than 402. All the ckt does is running lites, but it gave me confidence. The trace from pin 7 of the 555 to the caps was bad; that took more time than soldering.I even replaced the 555 before finding the issue. Now I know I can desolder as well.You certainly need tweezers for measuring SMD caps.Was trying to figure out what EEE stood for until I realized it 333! Lot to learn.

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 12, 2024, 08:20:47 pm
content: Quote from: watchmaker on October 12, 2024, 07:41:07 pmI've done a few of those test/learning boards before I got into SMT. It really is helpful.The good news is that my LCR boards are generally hand-solder pads, so you have extra room to solder if you don't have hot air.Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: October 12, 2024, 08:36:13 pm
content: QuoteI still remember my first attempt over 10 years ago....Test board, SMD solder paste applied, then various 1206 capacitors placed on the corresponding pads.And then I switched on the “SMD hot air tool” from the lab, held it on - and all the capacitors blew away with it....

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 12, 2024, 08:49:50 pm
content: Quote from: Martin72 on October 12, 2024, 08:36:13 pmClassic!The boards I used went down to 0402 and 0603. I watched a youtube video before attempting, and it said to be careful of the hot air pressure. 😉

author: watchmaker
author_rank: Unknown
timestamp: October 12, 2024, 09:03:26 pm
content: Interesting. I do have a got air gun but I just used my Ersa Pico. I put some solder on one pad, pinned one end or one leg and did the other(s) and went back.Also used flux paste applied with toothpick at times.What are the ways this task is done? Given the cost differential, I can see the advantages of SMDs. OTOH, not sure I want to go down the rabbit hole of PCB design. I wonder if I could do something using protoboard?

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 12, 2024, 11:35:20 pm
content: That's a good start. There are other videos, but in general, Pace has awesome stuff.Martin should pay attention to this one too. 😉😉

author: Kean
author_rank: Unknown
timestamp: November 12, 2024, 10:25:55 am
content: I've had the LCR Cal PCBs sitting here for over a month, and last week I finally got around to ordering the components.My Mouser shipment arrived today with 37 little bags of parts (a few are for another project).I don't think I'll be setting this job up on the PnP...Fun times ahead. Thanks Josh!

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 12, 2024, 03:27:56 pm
content: Hurry up and build it, everybody wants to know what color PCB you chose. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 07, 2024, 04:37:49 am
content: I decided I wanted a slightly different board for DMM testing, so I made one. There's some overlap with LCRs on there too, so I improved the Kelvin connection setup. Now all the Kelvin connections use split SMT pads, and sense/source are consistently marked.Whatcha think?Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 08, 2024, 09:05:44 pm
content: Scratch that lol. I realized I don't want 2 test boards, so I combined the LCR and DMM stuff.Any thoughts before I impulsively order these?

author: Martin72
author_rank: Super Contributor
timestamp: December 08, 2024, 09:54:55 pm
content: You design the circuit boards in your sleep, don't you...I probably won't finish populating my circuit board until I've bought a new soldering station; I'm not satisfied with the one I have now.In principle, I find the idea of being able to test as much as possible with a single board appealing.The design so that the Kelvin clamps fit is also good.If I were to design something like this, however, I would reduce the number of measuring components and implement the line paths as shown on the L/C option of DMM Check+.Even if it wouldn't be necessary due to the option of using Kelvin lines, it would be for gut feeling.Maybe I will do that, because we had two options to choose from.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 08, 2024, 09:58:17 pm
content: The line method on the L/C option makes it so you can't use kelvin clips at all, and that's half the purpose of this design. 😉

author: Martin72
author_rank: Super Contributor
timestamp: December 08, 2024, 10:17:16 pm
content: You can also measure on the board with Kelvin clips, I know that for certain reasons.But yes, the compensation then only goes as far as the test pins, that is true.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 18, 2024, 03:00:25 am
content: V6 is done. I'm going to test a few meters including my LCR, and at least 2 of my DMMs...as soon as I get my DAQ back from being serviced.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 18, 2024, 03:59:44 am
content: A few quick tests to see how it came out...

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 19, 2025, 11:20:04 pm
content: I sent my IM3570 out for calibration, and got it back yesterday. I'm pissed off at Hioki, because all they did was damage my LCR and confirm that there was nothing wrong with it before sending it to them (no adjustments needed), and charged me $512 for that. They somehow melted the top left corner of my LCR.That amateur hour bullshit aside, I used it to test against 2 ST2832s. Results attached.Thanks,Josh

author: Martin72
author_rank: Super Contributor
timestamp: June 20, 2025, 05:58:59 pm
content: Respect for the effort.The ST2832 meters are simply good; that's the conclusion you can draw from comparing them with the undoubtedly better Hioki.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 20, 2025, 06:19:55 pm
content: Thanks!Yes, and that's a good thing considering the price difference.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 05, 2025, 01:01:42 am
content: Anybody interested in sending around the V5 loaded PCB and comparing readings from their LCR meters?I can share the Excel spreadsheet with the readings Mike and I got from it, and people can add their own data.

author: 1audio
author_rank: Frequent Contributor
timestamp: August 05, 2025, 04:54:51 am
content: I'm interested. I have an ESI videobridge and an assortment of standards. it would be interesting to compare. I might also fire up the Bode 100, a low frequency VNA that can plot impedance vs frequency. Your card is small so the shipping should not be too bad.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 05, 2025, 01:53:31 pm
content: Shipping in the US should cost less than $10, even if sending priority. It would be nice to get a list of a few people so you can communicate and send it to each other. I'm just going to ship once.