ET4410 readings wildly fluctuate at 100Hz, stable at 120Hz - Page 1
Forum section: electronics / testgear

author: hp3310a
author_rank: Regular Contributor
timestamp: August 01, 2025, 07:55:04 am
content: I got me a new ET4410 LCR Meter and am only getting to know it, so here we go...When measuring a 10nF Chinese ceramic capacitor at 100Hz and 1V, the readings (C and ESR) wildy fluctuate (from mF to pF, basically random numbers). When I increase either frequency to 120Hz or the level to 1.5V, the reading stabilizes (and to a reasonable value). I measured a number of those same 10nF caps and a 1µF cap from the same Chinese source and they all make the meter behave the same.Measuring a KEMET 33pF, the reading is stable at 100Hz out of the gate, though the ESR shows unreasonable/impossible values.I noticed that sometimes after measuring the cap at 120Hz, going back to 100Hz sometimes the meter behaves correctly, most of the times it doesn't.Is my ET4410 faulty, or is this a user error?In case it matters, I'm using an SMD tweezers fixture (this onehttps://www.aliexpress.com/item/1005007309461933.html) with the meter. I should also note that I'm in Europe with 230V/50Hz mains (I read sometime back that one user had strange mains frequency related problems - though I no longer can find it).

author: Kean
author_rank: Unknown
timestamp: August 01, 2025, 01:24:56 pm
content: This might be the other post you were thinking of - although they had issues with higher value (milli Farads) - and at 120Hz, but note that they were in the US with 120V and 60Hz.https://www.eevblog.com/forum/testgear/east-tester-et4410-desktop-lcr-meter/msg5924182/#msg5924182In this later post they noted that they had the mains selector set wrong, which once fixed seemed to correct the issue.https://www.eevblog.com/forum/testgear/east-tester-et4410-desktop-lcr-meter/msg5925992/#msg5925992

author: mawyatt
author_rank: Super Contributor
timestamp: August 01, 2025, 01:53:11 pm
content: When making LCR Measurements it's always a good idea to have the meter display the DUT Voltage and Current. This gives an indication of the "quality" of the readings.For example: a 33pF capacitor at 100Hz has an impedance of ~48MΩ which might hint at the "impossible ESR readings"!!Best

author: hp3310a
author_rank: Regular Contributor
timestamp: August 01, 2025, 04:51:04 pm
content: Quote from: Kean on August 01, 2025, 01:24:56 pmYes, that's the one, I remembered after posting that the solution had nothing to do with the meter itself. Thanks!

author: hp3310a
author_rank: Regular Contributor
timestamp: August 01, 2025, 04:51:51 pm
content: Quote from: mawyatt on August 01, 2025, 01:53:11 pmOK, thanks but how do I do that, I don't think I can make the ET4410 show the current.

author: mawyatt
author_rank: Super Contributor
timestamp: August 01, 2025, 04:59:07 pm
content: Quote from: hp3310a on August 01, 2025, 04:51:51 pmCheck the manual on the ET4410, we don't have one, but some other bench type LCR Meters have the ability to show Voltage across DUT and Current thru DUT.Best

author: Martin72
author_rank: Super Contributor
timestamp: August 01, 2025, 09:41:52 pm
content: The ET44 series does not have U/I monitoring, which would be somewhat surprising for a $200 device (the ET35 series does have this).I kept my ET4410 as announced, and I have “Bo Jack” Chinese ceramic capacitors. I will repeat the measurements tomorrow.Without getting ahead of ourselves, it is rather unusual to test capacitors in the nF or even pF range at 100/120 Hz.Higher frequencies, 1 kHz or 10 kHz and higher, are more appropriate.

author: hp3310a
author_rank: Regular Contributor
timestamp: August 02, 2025, 10:10:30 am
content: Quote from: Martin72 on August 01, 2025, 09:41:52 pmIf you find time to repeat the measurement that would be fantastic, thanks a lot! I could send you a couple of the caps if you're interested.Quote from: Martin72 on August 01, 2025, 09:41:52 pmOK, good to know, thanks.

author: Kean
author_rank: Unknown
timestamp: August 02, 2025, 10:50:21 am
content: Quote from: hp3310a on August 02, 2025, 10:10:30 amhttps://www.easttester-cn.com/uploads/ET44-Series-lcr-meter-user-manual-.pdfTake a look at the accuracy specification and extra detail provided in section 8 of the user manual. There is a chart there that helps to show when you leave certain measurement accuracy bounds, although it is a little tricky to interpret because you need to look at the intersection of lines going up/down for frequency, then left/right for R, or diagonally for L or C. It also uses logarithmic scales.There are also formulas provided for calculating accuracy in ideal conditions. Note the units mentioned below the table, so for 100Hz Cmin is 15.9nF and Cmax is 15.9uF, and anything outside that has left the 0.1% accuracy spec. You can obviously measure outside these bounds, but the errors quickly increase as you move further away from them. Other factors like measurement speed and measurement level can also have a large effect.As Mike alluded to "a 33pF capacitor at 100Hz has an impedance of ~48MΩ", so you can also do some rough math to estimate the impedance of the component at the measurement frequency. If the impedance is really low or high then the voltages or currents involved can be tiny and measurements are naturally going to dominated by noise. This is why devices with V/I monitoring are very useful for unknown DUTs and verifying the settings are sensible.

author: Martin72
author_rank: Super Contributor
timestamp: August 02, 2025, 01:02:42 pm
content: I have now tried this out.ET4410 and ST2830 (the little man's reference), SMD test fixture, because I don't have any wired values below 1n at home.Therefore, ceramic SMD multilayer capacitors, 33p and 10n.First, I was able to reproduce the behavior, not on the 33pF capacitor, but on the 10nF capacitor.I then played around with the ET4410 a bit and think I know why it does that—if it does, because it's not always the case.At the moment, I assume that the auto range mode is triggered at low frequencies and low capacities.I had this behavior at 100 Hz, but not at 120 Hz, and then I got around it with the following trick:Lock...When the capacity display is stable, switch the mode from Auto to Lock, then the meter has the range and also shows the correct value at 100Hz.As I said, it doesn't always happen, but when it does, you can work around it.I then repeated the measurements on the ST2830, and as expected, this device had no problems.It has U/I monitoring and the current values are very low with the 10nF capacitor and extremely low with the 33pF capacitor, see pics(Vm / Im in the Display).So I can forgive the ET4410 for the behavior I observed.(The more you know, the less confusion there is.)

author: hp3310a
author_rank: Regular Contributor
timestamp: August 02, 2025, 03:38:03 pm
content: Thanks for digging into this and the workaround. My ET4410 seems to have listened in on the conversation and wasn't repeating the behavior AT ALL. Until I shorted the leads, that seems to have triggered it again.The Range feature and workaround doesn't seem to be working consistently for me, but I don't care. It's good to know that it is "supposed to" behave like that and the real workaround is not using the low testing frequencies for these type of caps anyway. Thanks again!BTW: It exhibits the behavior only with the 10nF cap, it behaves correctly with the 33pF.

author: Martin72
author_rank: Super Contributor
timestamp: August 02, 2025, 03:56:51 pm
content: QuoteSame here.Depending on the value, the 10nF may just exceed an internal switching threshold.

author: hp3310a
author_rank: Regular Contributor
timestamp: August 25, 2025, 06:45:48 am
content: Quote from: Kean on August 02, 2025, 10:50:21 amI paid too little attention to this... thanks for pointing me to it! The chart is rather eye-opening, the 0.1% accuracy only applies in a very narrow window of values/frequencies. You can easily get to > 2% with "regular" values of 1nF for caps for example - regardless of measurement frequency.I'm wondering if all these devices share the same narrow basic accuracy window or if this is a ER4410 specialty. I measured a bunch of 0.1% resistors the other day (decades from 0.1 to 10M) and for some values the readings where outside the tolerance for all of them. Could be the resistors (sourced a Aliexpress) but how to tell if the meter is so inaccurate.

author: mawyatt
author_rank: Super Contributor
timestamp: August 25, 2025, 12:37:44 pm
content: Quote from: hp3310a on August 25, 2025, 06:45:48 amCheck the resistors with a quality high resolution DMM.Best

author: hp3310a
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:00:12 pm
content: Quote from: mawyatt on August 25, 2025, 12:37:44 pmMy 34401a does agree with the nominal value of the resistors much more closely. I guess it's better suited to measure resistance, but I don't have a Kelvin fixture for SMD components for it, so for lower resistance values it is unreliable (for 0.1% precision resistors).As for the ET4410, after reviewing the accuracy chart again, I think it may be within its own tolerance for the specific values I measured and assuming the resistors in question are better than 0.1% (the 34401a says they are). My mistake was to assume 0.1% basic accuracy applies to all ranges.But my initial question still stands: Do other LCR meters come with such a fuzzy definition of basic accuracy, too, where the given accuracy applies only to a very narrow window of component values?

author: TimFox
author_rank: Super Contributor
timestamp: August 25, 2025, 05:12:44 pm
content: Your country tag is not set: are you in 50 or 60 Hz territory?

author: hp3310a
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:39:04 pm
content: 50Hz, I updated the profile accordingly.But why does it matter?

author: TimFox
author_rank: Super Contributor
timestamp: August 25, 2025, 05:48:29 pm
content: Quote from: hp3310a on August 25, 2025, 05:39:04 pmPossible beat between sample rate or test frequency and line-frequency interference.

author: Martin72
author_rank: Super Contributor
timestamp: August 25, 2025, 06:03:52 pm
content: Quote from: hp3310a on August 25, 2025, 05:00:12 pmYes.Every LCR, regardless of how expensive it is, has a “sweet spot” or “sweet area” where it measures most accurately; this is known as “basic accuracy.”

author: hp3310a
author_rank: Regular Contributor
timestamp: August 26, 2025, 04:47:46 am
content: Quote from: TimFox on August 25, 2025, 05:48:29 pmI tested at frequencies from 100Hz to 4KHz, the resistance readings were consistent. Settled with 200Hz for the bulk.Quote from: Martin72 on August 25, 2025, 06:03:52 pmThanks, so I take it thowing money at it will widen the "sweet area" but not eliminate it.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 26, 2025, 04:50:59 am
content: Quote from: hp3310a on August 26, 2025, 04:47:46 amTake a look at the attached accuracy chart for the ST2830/ST2832. It gives a better visual of what the sweet spot looks like. Even outside the sweetest sweet spot, it's still good until you go too far out. At that point, you need to consider the type of instrument you're using to measure with and what kind of accuracy you really need (among other details like test setup, technology, budget, etc.).

author: hp3310a
author_rank: Regular Contributor
timestamp: August 26, 2025, 07:27:47 am
content: Quote from: KungFuJosh on August 26, 2025, 04:50:59 amThanks for that one, great to have a format that makes a comparison easy.Incidentally I came across this chart - kind of - reading the manual of a Jinko Brand LCR meter JK-2817N (available from Alibaba). Miraculously it has the exact same diagram, only the accuracy border lines are missing (and the value lines, but those can be traced). Hmm.