Bench LCR Recommendations?

[Martin72]

780$...965$...The sourcetronic ST2832 cost 1700€....and it´s the same.
So for me it wouldn´t be a question to buy the Tonghui or not, but "unfortunately" I have a hioki LCR(I have to reassemble after repair)...
I know the DE5000, I know the ET4410, I know the "little" (but more expensive) brother of the Tonghui and this would be my ranking:

DE5000 - "Best" handheld you can get for appx 150 bucks, good accuracy.
ET4410 - Cheap but good benchmeter, slightly better than DE5000, more features like list function, scpi command set, dc-bias voltage, higher testvoltage (selectable), more selectable testfrequency steps (15).
ST2830 - Next step when ET4410 is not enough in building quality, slightly more precise measurements in general.
TH2830(ST2832) - Would be my personal favorite with testfrequencies up to 200khz and dc-bias voltage avaible, plus the accuracy and build quality of the ST2830, but cheaper...weird.

[KungFuJosh]

TH2830(ST2832) - Would be my personal favorite with testfrequencies up to 200khz and dc-bias voltage avaible, plus the accuracy and build quality of the ST2830, but cheaper...weird.

I think the model numbers are directly related. For example, TH2830 = ST2830, TH2832 = ST2832 etc. I think it's one of those things where you can buy a certain quantity and Tonghui will rebrand it for you.

The TH2830 also only goes to 100kHz, but the TH2832 goes to 200kHz.

I like the DE5000 also, I still have mine.

[coromonadalix]

and the 2831 is less precise   wut ?

[KungFuJosh]

and the 2831 is less precise   wut ?

It's listed as EOL on their website. Maybe the older version of the TH2832? That would be my guess.

[pope]

How about these? They seem impossible to buy them in EU...

https://www.szmatrix.com/collections/lcr-meter

[KungFuJosh]

How about these? They seem impossible to buy them in EU...

https://www.szmatrix.com/collections/lcr-meter

I was considering them, but I don't like the display or front panel design. I also watched some videos on the MCR-5X00, and getting to different test modes is clunky in the menu. That, and it's really close in price for me to the TH2830, but doesn't come with the nice fixtures the TH2830 comes with. I do like the range of the MCR-5200, but it's also listed as .1% accuracy, whereas the TH2830 is .05%. If there was a bigger price gap, I would consider it.

The newer MCR-6000 series has a nicer screen and better accuracy and range than the 5000 series, but it's more expensive than the Tonghui. Also not really available yet. Maybe in a year or something they'd be a better deal.

[KungFuJosh]

I didn't hear back from Tonghui, so I bit the bullet and bought it from one of the sellers I was considering on aliexpress. Now I get to wait impatiently until it arrives from China.

[KungFuJosh]

🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣

Well, apparently, the seller I chose NOT to purchase from was the correct choice. I was tempted because they offered the TH2830 to me for only $650 including shipping. Which sounded too good to be true. Naturally, I was skeptical. I asked them to send me photos of the actual product, to confirm it was genuine Tongui, and brand new. They sent me screenshots from their ad. 🙄

So I told them: "I'm purchasing from another seller that's been around longer, with more feedback. Best of luck, thanks anyway."

They responded (copied and pasted sixteen times like a child): "You are an idle person, asking me countless questions, and I also replied to you to cancel the order in the end.You are not a real businessman, you are a dishonest It takes me so much time and energy to reply to so many of your questions You are just a loser without anyone's credibility and integrity"

Needless to say, avoid "EVERGOOD INSTRUMENTS Store" at all costs. They've been on aliexpress for less than a year, and they are clearly not trustworthy. I'm glad I dodged that bullet.

[KungFuJosh]

Good news and bad news.

The good: The seller shipped fast with DHL express, I received it today.

The bad news: the unit appears to be used.

The other bad news: the reason these aren't commonly sold in the US is it appears they require 220V power. That wasn't listed in the ad, and the pics of the unit weren't clear enough to see that.

No snarky RTFM comments please. 🙄

[Martin72]

When our sourcetronic arrived from calibration, I could look inside if there is a input voltage switch avaible.

[mawyatt]

Good news and bad news.

The good: The seller shipped fast with DHL express, I received it today.

The bad news: the unit appears to be used.

The other bad news: the reason these aren't commonly sold in the US is it appears they require 220V power. That wasn't listed in the ad, and the pics of the unit weren't clear enough to see that.

No snarky RTFM comments please. 🙄

Interesting about only 220VAC, ours was requested for 120VAC, assured it would be so, and works fine on such and came with standard US 120V plug. You should ask Tonghui about this, maybe there's a jumper inside to set to 120VAC?

Good luck with yours,

Best,

[KungFuJosh]

Thanks guys, hopefully you're right. Worst case if I get stuck with it, I could hopefully find a replacement transformer.

The seller thinks it works with 120V, but the back panel and manual don't agree.

It's possible there's a dual voltage transformer inside, but there's also a "calibration void if seal is broken" sticker on the back panel of the enclosure.

The fact that they lied about it being new is annoying too.

[mawyatt]

Ok, couldn't resist to help out. Took the TH2830 out of series and took the cover off (easy 3 screws), no Cal label to deal with!!

The special transformer has 4 wires from the primary, red, blue, black, and yellow/green (ground/shield). One shows 110VAC, the other 220VAC and in series with the other.

Note the short red wire jumper in the white connector with the red and blue wires that go to the AC input & fuse connector, this likely is the jumper that sets up for 110VAC or 220VAC operation.

If you open yours, take a look and see if the red jumper is in place? You could buzz out the connections to see if the assessment above is correct. Does the seller know anything regarding this mains setup?

Anyway, I wouldn't do anything before contacting Tonghui, and does look like you'll be able to configure for 110VAC use. However, please don't do anything without some conformation from Tonghui as we certainly don't want a fried lab LCR meter on our hands

Best,

[mawyatt]

Another view.

Best,

[KungFuJosh]

Thank you. Assuming it has the same transformer and connections, I would disconnect the clips and verify the output voltage before reconnecting them to the board. However, I'm not in a rush to pull the back panel and cut the sticker yet. I want the seller to resolve the used vs. new issue also.

[KungFuJosh]

Does anybody know if the TH2830 has a usage stats thing in the menu somewhere? Like how many hours it has been used, or how many times it has been turned on?

[KungFuJosh]

This appears simpler than expected.



I buzzed out the connections, and they are as follows:

2A to 3A
3B to 4B

1A to 1B
2A to 5B
3A to 5B
4A to 6B

C shows reference voltages:
C1 and C4 = 12VAC
C6 and C7 = 7VAC

Comparing Mike's jumper wire, it's as simple as moving the jumper wire on mine from B6 to B5 (my jumper was connecting B4 to B6, Mike's is B4 to B5).

Thanks,
Josh

[KungFuJosh]

Ok, couldn't resist to help out. Took the TH2830 out of series and took the cover off (easy 3 screws), no Cal label to deal with!!

THANK YOU!!!

Swapping the jumper wire (see above) did the trick. I tested the secondaries for the marked voltage, and pins 6 and 7 had 8.9377VAC unloaded, and pins 1 and 4 showed 2.6634VAC. Maybe it really says 1.2VAC instead of 12VAC, or maybe it's 12VAC when actually powered on. 🤷

This test showed that the transformer is pushing that voltage to pins 6 and 7 even when the unit is powered off. I'll be shutting this off with my surge protector when my bench isn't in use.

Anyway, I reconnected the PT secondary to the PCB, and it powered up. Thankfully it didn't take too much effort to change it to English. Now to learn how to use it. 🤣

Thanks,
Josh

[KungFuJosh]

Okay, first of all, the fixtures are legit. They're as heavy as some of my meters lol.

I calibrated with the TH26048A fixture, and tested a cap:

UKZ2A220MPM 22uF 100V electrolytic cap.

100Hz:
TH2830 said: 20.0353uF, ESR=2.97802 ohm
DE5000 said: 20.06uF, ESR=2.9 ohm
Shannon tweezers said: 19.97uF, ESR=2.7 ohm

The reading on the TH2830 isn't super stable. Is that normal? It's only the last digits shifting.

What are your firmware versions? Mine says v1.0 at startup. I'm guessing that's not awesome?

Thanks,
Josh

[mawyatt]

Nice, good news

Ours is also V 1.00, so no worries!! It's also stable, we exclusively use the "Slow" speed and Avg 16 (see Measure Setup Menu) since we're not a production line.

Also turn Vm/Im ON (Setup Menu) so you can "see" the DUT measurement Voltage and Current. Very important feature that few folks utilize, as this helps the knowledgable user regarding the quality of the measurement at hand, with a very low DUT voltage or low current, one should question the displayed result!!

Please, please spend some serious time understanding how these bench lab grade quality LCR meters operate, and how they compute the various displayed parameters from the DUT voltage and current (vectors) measurements, this knowledge is important if one expects to utilize these fine instruments to their fullest extent!!

Now get yourself some quality caps, ceramic C0G/NP0 only, film types like Polystyrene or Polypropylene (not mylar), and some mica types. These will come in handy to verify that something hasn't gone astray with future measurements if you make some quality early measurements and keep a record of such, when something doesn't seem right then check with a known good capacitor as a sanity check.

Here's a good source in the US we've used, lots of surplus selections on all sorts of capacitors and other items.

https://www.surplussales.com/GuestTools/shoppingcart.html

Also consider building the DC Bias adapter, details here.

https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/

And of course sooner to later (likely sooner) you'll want to employ your new lab grade bench LCR meter for SMD devices (you can use the DC Bias adapter with this also), so get yourself one of these and modify as we've shown.

https://www.eevblog.com/forum/testgear/cheap-smd-lcr-fixture-the-good-bad-and-ugly!/msg4539458/#msg4539458

Then you'll likely want the nice plots you've seen from these bench type LCR meters, which you can probably buy the software from somewhere (expensive from Tonghui ?), or just purchase the crude Python code versions we created (maybe spruce it up a little!!), this only cost a brew 

https://www.eevblog.com/forum/testgear/lcr-meter-plot-software/msg4774100/#msg4774100


Edit: Forgot to mention, check out the frequency resolution it's not just 37 points as indicated in the manual. Try this, enter 12345 and Hz using the keypad, and note the display it's 12.345KHz, or 987.654Hz, or 31415Hz! It's DDS driven, nice


Have fun

Best,

[KungFuJosh]

Thanks for your help and the tips!

I already have plenty of caps for reference, not sure about the ceramic types though. I'll get some if I need to. I'll make a reference chart with a set of specific caps, and cross check them on the DE5000 and Shannon tweezers.

For SMT stuff, for now I'm just going to keep using the Shannon tweezers, but I may setup a SMT fixture also in the future.

Thanks for the tips on the measure setup- Avg 16 is much more stable, and I'm sure plenty accurate enough for my needs.

I turned on Vm/Im, what do you consider very low?

I wonder, has anybody done a hardware comparison between the TH2830 and TH2832? What I really wonder is if there's any difference between them besides their firmware and the sticker on the front.

[mawyatt]

Just measure an open and short, that will give you an idea of what's to be considered as low for current (open) and voltage (short). Note you can change the output Z to 30 ohms for high current use with low impedance DUTs, and the output voltage to 2 volts for high impedance DUTs. Also study up on the ALC use (3.5.2), which can maintain a constant Voltage or Current for the DUT.


Edit: CAUTION, this instrument can deliver 2 volts RMS and 67ma RMS to the DUT, so some caution is advised when evaluating sensitive DUT characteristics.

Anyway, lots of useful features and whatnot in these instruments, and lots of details to learn to use properly

Best,

[KungFuJosh]

I setup a test with 3 LCRs and 3 other meters. Results attached.





The Siglent and Amprobe meters agree a lot. Even their BS numbers when trying to measure in the pF were similar.

The ESR numbers marked unstable were wonky. They had a fairly large range they cycled through. I assume it would be easier at a lower frequency, but 1k it was.

[Martin72]

Testfrequency is missing..
Comparing with a bench DMM is a little bit "unfair" because I strongly doubt that the DMM use the same measure method like the LCRs do.

[KungFuJosh]

Testfrequency is missing..
Comparing with a bench DMM is a little bit "unfair" because I strongly doubt that the DMM use the same measure method like the LCRs do.

Test frequency for the LCRs is 1kHz (noted on the spreadsheet). It wasn't really intended to be fair for the other meters, they were just added for reference. I don't think it's generally fair to compare C measurement on a DMM anyway. It's just nice that they say something. Though I found it interesting how close the 2 DMMs were, in their measurements and failures.