Fnirsi LCR-P1, $30 LCR tester (August 2024)

[BillyO]

FNIRSI LCR P1 - Does it know how to measure ESR and does it measure correctly?"

Well, first, even LCR meters that cost in the hundreds or even thousands of dollars have a very hard time agreeing on what the ESR of a given capacitor is.  Given that what are your expectations on the accuracy of a $30 device?

Yes, the LCR-P1 does measure ESR.  I don;t know how accurate it is yet, but I have bought one and it should be with me soon.  I will report here what I find.

The TC2 and TC3 are primarily scopes.  The TC3 does have upgradeable firmware and I do not believe FNIRSI have abandoned it.

[Andrey_Ak]

Here's a comparison, the first three devices show correctly.
And the fourth column is the readings of the fake Chinese tester T7 (former TC1).

https://tis.kz/temp/20240908_223153.jpg
https://tis.kz/temp/20240908_223256.jpg

[indman]

FNIRSI LCR P1 - Does it know how to measure ESR and does it measure correctly?"

Well, first, even LCR meters that cost in the hundreds or even thousands of dollars have a very hard time agreeing on what the ESR of a given capacitor is. 

We don't need to expound nonsense. A responsible capacitor manufacturer always accompanies its products with a technical description and characteristics, which also indicate the ESR or Z limits at a certain frequency, temperature, etc. There are quite strict conditions for measuring parameters at the manufacturer's factory.
Instruments for MEASURING capacitor parameters must meet these conditions. That's all we need to know.

Yes, the LCR-P1 does measure ESR.

No, it does not MEASURE ESR, but only SHOWS some result on the display. These toys cannot measure ESR by definition and due to their hardware.

The TC2 and TC3 are primarily scopes.  The TC3 does have upgradeable firmware and I do not believe FNIRSI have abandoned it.

TC2 and TC3 are positioned as 2 in 1 devices. Which part is more important here is difficult to say, since both are just parodies of measuring instruments. FNIRSI usually drop support for their products as soon as they release a new product with similar content to the market.

[Andrey_Ak]

TC2 and TC3 are positioned as 2 in 1 devices. Which part is more important here is difficult to say, since both are just parodies of measuring instruments. FNIRSI usually drop support for their products as soon as they release a new product with similar content to the market.

I completely agree with you.
I hoped that something had changed with the release of the LCR-P1, that they could at least make just a transistor tester normal, without useless toys "oscilloscopes", "generators"..

[BillyO]

Oh goody, the God of metrology chimes in in our discussion of sub $30 devices.

A responsible capacitor manufacturer always accompanies its products with a technical description and characteristics, which also indicate the ESR or Z .. blah, blah, blah...

Yet, three different top end LCR meters WILL measure a given capacitor differently even when the measurements are done to spec.  Prove me wrong.  You are lucky if you end up with agreement within 10%-15%

Besides, measurement of ESR should ideally be done based on application, not spec sheets.  At best they are a guide.  ESR is dependant on voltage, frequency, temperature and the color of your great aunt's underwear.  If you need a specific limit on the ESR of a capacitor, it should tested against the conditions of the application.

No, it does not MEASURE ESR, but only SHOWS some result on the display. These toys cannot measure ESR by definition and due to their hardware.

By what definition?  (word salad alert)  Yes, blah, blah, blah ...

Get off your high horse here!  We are talking about things that cost $30 or less.  We're not talking about a Keysight E4980A here so trying to compare these things to something like that is truly expounding nonsense.  Not everyone can afford an E4980A, and that's a cheapie in the Keysight lineup.  And if you are looking for one of these $30 devices to give $30,000 results, your an idiot.

So, let's compare McDonald's burger patties to Kobe beef tenderloin next.  Make sense?

The internet 

[indman]

No, it does not MEASURE ESR, but only SHOWS some result on the display. These toys cannot measure ESR by definition and due to their hardware.

By what definition?  (word salad alert)  Yes, blah, blah, blah ...

Don't embarrass yourself by spouting your nonsense here.

[KungFuJosh]

ESR is dependant on voltage, frequency, temperature and the color of your great aunt's underwear. 

What if she went commando? 🤔

[BillyO]

What if she went commando? 🤔

All bets are off!

[Phil1977]

I really like a few of the FNIRSI products (thinking about the SG04...) but I´m absolutely not convinced of their transistor tester clones.

For well below $30 you can get a good version of the original transistor tester, capable of using the open source software and being supported by its community. And usually the good versions even deliver a usable ESR value.

Why do you want to buy a closed source tool that doesn't care a tiny bit about the open source nature of its core design? Just because of the fancy housing?

[BillyO]

Don't embarrass yourself by spouting your nonsense here.

No answer, eh?

There are multiple ways you could measure ESR.  Even using step functions like these cheap things do.  Bur please, tell us the definitive way?

All this nonsense aside, these are handy and useful devices if you get one that's decently made.  However, measuring actual ESR is not one of the things I would ever use one for.  ESR is not easy to get accurately for a host of reasons no matter what method you use.  That's why a decent ESR meter costs $30,000.  Even still, you could use the "ESR" reading on one of these usefully.  Like comparing a new electrolytic capacitor that measures "X" to and old suspect one that measures "5X".  You don't really need to know the exact ESR to determine if something should be replaced.

I hate bullies and snobs.

I'll give you the last word.

[KungFuJosh]

That's why a decent ESR meter costs $30,000.

I'm sure some excellent ESR meters cost that much, but nice meters exist well below that.

For example:
https://www.mouser.com/ProductDetail/647-UHE1H102MHD3TN

According to Mouser and other retails: UHE1H102MHD3TN has an ESR of 21mΩ. (the datasheet only specifies the max/min ESR)

My office right now is 24.4C (76F) and 39% RH.

IM3570 @ 1kHz:
Cap 1: 27.69mΩ
Cap 2: 26.20mΩ
Cap 3: 25.96mΩ

3532-50 @ 1kHz:
Cap 1: 26.41mΩ
Cap 2: 25.86mΩ
Cap 3: 25.82mΩ

Even the humble Shannon ST42 did well.

ST42 @ 1kHz:
Cap 1: 23.52mΩ
Cap 2: 20.81mΩ
Cap 3: 20.08mΩ

It might be relevant to note that the ST42 is the only device I didn't do a fresh open/short correction with.

With a target of 21mΩ from Mouser, I think all 3 meters did pretty well. 🤷

Thanks,
Josh

[Circlotron]

What's the new type transistor I've underlined in red?  

Looks like a miosprint.

[BillyO]

With a target of 21mΩ from Mouser, I think all 3 meters did pretty well. 🤷

Thanks,
Josh

Yes, I'd agree.  Not quite within the 10%-15% I had mentioned over all 3, but what I'd generally expect from past experience.

You have quite a range there from $15,000 to $170 though.  The ST42, not being calibrated might have gotten lucky 

Now, what would you expect for a sub $30 instrument that had no way to set any testing parameters?

[KungFuJosh]

Yes, I'd agree.  Not quite within the 10%-15% I had mentioned, but what I'd generally expect from past experience.

You have quite a range there from $15,000 to $170 though.  The ST42, not being calibrated might have gotten lucky 

Now, what would you expect for a sub $30 instrument that had no way to set any testing parameters?

You can't expect results within 10% of a stated number without knowing the actual test frequency and room temp. Considering my office was still warmer than typical labs, and none of my meters have an active cal cert, I'd say it was pretty awesome. I could have changed the test frequency to match the ESR better, but I picked 1kHz since it's pretty common. ESR is dead on at 118 kHz (attached). 😉😉

The ST42 was open/short corrected yesterday. I think it wasn't much to do with luck. 😉 I have to correct the bench meters more frequently because I'm always changing fixtures.

I've mentioned before in these threads, I would never use or recommend any of the Fnirsi or TC1 type devices for anything other than transistor testing/identification. The small exception being the DSO-TC3, with which the scope mode was sometimes useful to test the outer foils on film capacitors...but I only really did that to test the TC3. I'd obviously stick with my Siglent HD scope for any real scoping.

ETA: All 3 test caps are nearly identical at 118kHz.

[BillyO]

You can't expect results within 10% of a stated number without knowing the actual test frequency and room temp.

Even then you can't expect within 5% even for $15K instruments.  ESR is a f'k of a thing to measure accurately.

You can get a $15K DMM and measure a voltage and it's going to agree with a $50 DMM to within 0.1%or better.  Same with ohms or current.  ESR, no bloody way. 

When I was the of the facilitator of the 4th year electronics lab at the University of Toronto back in the late '80s we had a lab on measuring ESR of capacitors.  The whole idea of the lab was to demonstrate there are physical properties of things (ESR of capacitors in this case) that are so entangled as to be almost impossible to ascertain to any high degree of precision.

Here, try this.  Take one of the capacitors you just tested on the $15K Hioki, test it again.  Now rotate the entire test setup physically by 90%.  Does it measure even slightly differently?  How about inserting the cap 10mm more into the fixture?  How about 10mm less?  How about standing off to the side?  Mabe leave a coffee cup close by?

There will be differences (if the meter gives enough precision), and that is with the same cap and same instrument.  BTW, I notice they don't have too any digits of precision in the ESR readings, do they?.  Dead giveaway right there.

Long argument made short ..  ESR measurement is never precise nor is it accurate.  Not even with tens of thousands of dollars spent.  With $30 spent, WTF do you expect?  And this is my whole point.

[Andrey_Ak]

FNIRSI's response from their official website:

https://tis.kz/temp/answer_fnirsi_LCR-P1.jpg

[Phil1977]

If you want to spend $30,- and get the best ESR estimation that is available then please take

- LCR tweezers like the Zoyi or Fnirsi ST1
- An ESR meter like the RC3563

If you want to get a capable transistor tester, then I can recommend the following:

https://de.aliexpress.com/item/1005004914474349.html

It´s only $10 and it uses a standard Atmel 328 MCU. I`m not sure if it´s an authentic one but you can change it in case of doubt.

I still don't get why people want to buy a closed source version of an open source project for 3 times the price 

[Phil1977]

Out of curiosity I checked a standard 1000uF/35V cap with 5 devices I just have available:

FNIRSI TC3: 987.9uF, 420mOhm
FNIRSI ST1: 905.1uF, 59.9mOhm
ET 432: 892.4uF, 71.82mOhm
ATMEL 328 Transistor tester: 926uF, 40mOhm
RC3563: 6.795mOhm

This test shows that the TC3 and RC3563 are ridiculously wrong. At least the two LCR meters are not worlds apart, and the "original" Atmel 328 is at least showing the right order of magnitude.

As soon as I find 30min of time for it I´ll do the ESR-check with the scope and waveform generator with the same cap.

[Aldo22]

If you want to spend $30,- and get the best ESR estimation that is available then please take

- LCR tweezers like the Zoyi or Fnirsi ST1
- An ESR meter like the RC3563

If you want to get a capable transistor tester, then I can recommend the following:

Funny, I was just about to write the same...

[Andrey_Ak]

If you want to get a capable transistor tester, then I can recommend the following:
https://de.aliexpress.com/item/1005004914474349.html
It´s only $10 and it uses a standard Atmel 328 MCU. I`m not sure if it´s an authentic one but you can change it in case of doubt.

I have a GM-328 with the original controller, it works fine. 
I want a complete, beautiful device in the case.

[Xena E]

If you want to measure ESR for a critical new product application do it properly with a scope!

If you have to measure capacitors to ensure good quality then change your supplier.

If you want to measure ESR in a repair situation and the fault indicates a duff capacitor just forget the friggin ESR measurement wankery, change the bloody thing and get on with your day.

We hand out those Fnirsi things to the field service techs, great for simple ball park checks, and there's no tears if they loose them or f*ck them up.

They could be better for the money, all their products could, and the specs could at least be honest (scope bandwidths are a big joke!) that would improve their reputation. To give to kids in a classroom to play with and study a 555 circuit though they're fine.

If you need lab grade equipment you have to pay for it. Comparing cheap hobby grade stuff with professional instruments is just stupid.

[BillyO]

They could be better for the money, all their products could, and the specs could at least be honest (scope bandwidths are a big joke!) that would improve their reputation. To give to kids in a classroom to play with and study a 555 circuit though they're fine.

They are definitely getting better at this.  The 1014D and 1013D were a mess in this respect but it seems they have learned something from teh experience.

If you need lab grade equipment you have to pay for it. Comparing cheap hobby grade stuff with professional instruments is just stupid.

I couldn't agree more.

[Phil1977]

If you need lab grade equipment you have to pay for it. Comparing cheap hobby grade stuff with professional instruments is just stupid.

There is exactly one good reason to do it: To learn about your equipment. There´s rarely anything more educational than analysing where the deviations come from. And sometimes even the expensive instruments display something non plausible - it´s always good to be able and to be used to cross-check your results.

[KungFuJosh]

Here, try this.  Take one of the capacitors you just tested on the $15K Hioki, test it again.  Now rotate the entire test setup physically by 90%.  Does it measure even slightly differently?  How about inserting the cap 10mm more into the fixture?  How about 10mm less?  How about standing off to the side?  Mabe leave a coffee cup close by?

See attached. I'd say the shift of .01mΩ at 90 degrees (I assume that's what you meant) is not significant. The cap gets inserted fully in the fixture. Pulling it out 10mm only adds inconsistencies and questions the fixture's mechanical hold on the DUT. It's easy to make measurements worse, but using fixtures and devices as intended helps a little bit. 😉

My office temperature is 69F right now. That's much closer to the datasheet, and typical lab temps. At 100kHz, the ESR is on target now. 100kHz is the freq with which the datasheet notes ESR.

Long argument made short ..  ESR measurement is never precise nor is it accurate.  Not even with tens of thousands of dollars spent.  With $30 spent, WTF do you expect?  And this is my whole point.

I'm not disagreeing with you. I do agree that measuring ESR is a big pain in the ass. However, if the tools are sufficient, and used properly, with known targets (ESR @ freq) and environmental conditions, it's a lot easier to get a probably reliable ESR reading.

I 100% agree with you about trying to measure ESR with $30 toys. Even if Fnirsi claims a device can test ESR properly, I won't believe them unless they're talking about a better brand. 🤣

[BillyO]

See attached. I'd say the shift of .01mΩ at 90 degrees (I assume that's what you meant) is not significant

Thanks for doing that test.  No, it's not really significant. but it is a demonstration that even in controlled conditions even something like minor environmental changes can make a small difference.  Placed in a circuit where there may be heatsinks, ground planes, and transformers close by the effects add up - possibly to being significant.  I guess that's why we have only two significant digits of decimal even on high end LCR equipment.

I'm not disagreeing with you. I do agree that measuring ESR is a big pain in the ass. However, if the tools are sufficient, and used properly, with known targets (ESR @ freq) and environmental conditions, it's a lot easier to get a probably reliable ESR reading.

Yes, as good as you're going to get.

I 100% agree with you about trying to measure ESR with $30 toys. Even if Fnirsi claims a device can test ESR properly, I won't believe them unless they're talking about a better brand. 🤣