LCR tweezers 100 kHz.

[tautech]

.......

Recall Dave, a year back, mentioned he would make a shoot-out on all these LCR tweezers that he's been sent over the years, incl. the ST42, but I doubt it materialized in a video.?
Could be interresting to see how they all stack up and their pro & cons..

Well he'd have to lift his game some as he couldn't get to grips with the ST3 years after I got mine nearing 2 decades ago.

Since replacing ST3 with ST42 it is fantastic to see how much LCR smart tweezers have developed from the time ST3 was top of the heap yet it doesn't even rate a mention against the far more modern and more capable ST42.

LCR is not all where smart tweezers are at, being able to update the FW to add new features and diode and LED testing is incredibly handy for the repair technician.....so much so I barely use a DMM now for any component testing.

[kripton2035]

I bought the zoyi MD2 and it's a nice little device, but it does not test leds (although it can test diodes) and it's a feature I would really like to have ! I hope someone will be able to build an alternative firmware for it as it seems relatively (!) open...

[iet]

FNIRSI has started selling its LCR-ST2 tweezers.
https://www.fnirsi.com/products/lcr-st2

[KungFuJosh]

Measuring ESR on datasheets is often done at 100kHz. That doesn't mean the tweezers are good at it.

What conditions, in your opinion, must be met for the tweezers to correctly measure ESR at a frequency of 100 kHz?

Start with known values and environment conditions, then test against a calibrated lab quality LCR meter. Test the same thing multiple times breaking and making new connections, and see what the results look like.

Were the devices properly calibrated before testing?
Are the results consistent and repeatable?
Do the tweezer results agree within reason with the lab grade machine?

Comparisons of these smart tweezers with professional LCR meters can only be carried out by a well-theoretically educated and trained specialist with extensive experience in these measurements.And it's better to open another separate topic for this.In this topic, we see only useless photos and idle chatter.

If any schmuck can use either device, then any schmuck can test them. Those of us with experience can determine if the results are meaningful.

There's no need for a separate topic since we're talking about the accuracy and reliability of the tweezers in this topic. Though a separate thread specifically for testing different LCR meters and tweezers from multiple brands could be fun.

Thanks,
Josh

[iet]

The basic parameters of the ST1/ST2 are practically identical. Only the ST2 tweezers have slightly expanded the number of new features.

[iet]

This video from FNIRSI already shows a significant difference from the ST1 - there is a short and open calibration.

[iet]

I bought the zoyi MD2 and it's a nice little device, but it does not test leds (although it can test diodes) and it's a feature I would really like to have ! I hope someone will be able to build an alternative firmware for it as it seems relatively (!) open...

I fully support you.
I'd also like to see two more features.
Add a menu option for simultaneously measuring capacitor ESR at 100 kHz and capacitance at 120 Hz. This will save time when testing capacitors where this is specified in the datasheets. You could look at the LCR-Reader R3 tweezers.
https://lcr-reader.com/R3/Downloads/Documents/LCR-Reader_R3_manual.pdf
Integrate DC/AC voltage protection between the probes and the input circuit of the tweezers. You could look at the LCR Elite2 tweezers.
https://www.lcrresearch.com/elite2
This also applies to the FNIRSI ST2 tweezers.

[iet]

FNIRSI LCR-ST2.
Resistors 0.1%.
100 R-100.0
150 R-150.1
301 R-301.0
2k-2.000
3k92-3.921
6k34-6.341
10k-10.00
68k1-68.09
80k6-80.65
100k-100.0
511k-511.5
681k-681.0
1M-1000
13k(0.05%)-13.00

[KungFuJosh]

FNIRSI LCR-ST2.

There's a separate thread for the ST2, and I shared a brief review of it there: https://www.eevblog.com/forum/testgear/new-lcr-tweezer-fnirsi-lcr-st2-(november-2025)/msg6128743/#msg6128743

[iet]

Test board. Capacitance measurement. UT622C,Pro1 Plus,ST2-1 kHz.
0.001 uF 2%
UT622C-1.0151
Pro1 Plus-1.0134
UT161E-1.034
ST2-1.015
0.01 uF 0.5%
UT622C-10.042
Pro1 Plus-10.041
UT161E-9.955
ST2-10.04
0.05 uF 0.5%
UT622C-50.265
Pro1 Plus-50.268
UT161E-50.28
ST2-50.25
0.0792 uF 0.5%
UT622C-79.730
Pro1 Plus-79.718
UT161E-79.78
ST2-79.75
0.1uF 0.5%(Mica)
UT622C-100.02
Pro1 Plus-100.02
UT161E-100.1
ST2-100.0
0.15 uF 1%
UT622C-150.26
Pro1 Plus-150.31
UT161E-150.37
ST2-150.2
0.165 uF 1%
UT622C-164.67
Pro1 Plus-164.70
UT161E-164.73
ST2-164.7
0.25 uF 0.5%
UT622C-252.23
Pro1 Plus-252.11
UT161E-0.2520
ST2-252.2
0.33 uF 1%
UT622C-331.7
Pro1 Plus-331.49
UT161E-0.3317
ST2-331.7
1 uF 1%
UT622C-1.0026
Pro1 Plus-1.0022
UT161E-1.0029
ST2-1.003