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I was struggling to identify a tiny, unmarked SMD capacitor on a circuit board, and guessing wasn’t cutting it. So I grabbed the FNIRSI LCR-ST2 100kHz LCR ESR Meter Tweezer to finally get some answers with its 100 kHz full-range scan.
This little tool is really for anyone who does electronics repair or hobby building. It handles both SMD and through-hole parts, and I like that it auto-sorts components to flag the bad ones. Just know the included storage pouch is basic, but the 300 mAh rechargeable battery keeps it going.
- 【All-in-One】FNIRSI LCR-ST2 LCR Meter for SMD & through-hole parts...
- 【Precise & Reliable Testing】Four RMS test levels...
- 【Primary/Secondary Display】Auto measurement with primary parameters...
What Stands Out — Key Features
- All-in-One Tester: This thing measures resistors, capacitors, inductors, diodes, continuity, and even voltage up to ±30V. I love that it auto-sorts and identifies abnormal components for you.
- 100kHz Full-Range Scan: It sweeps from 100 Hz all the way up to 100 kHz, which I found handy for testing everything from RF parts to large electrolytic capacitors.
- Primary/Secondary Display: You get the main value like capacitance or resistance, plus secondary info like X, D, Q, or θ. It made my diagnostics way more thorough.
- Four RMS Test Levels: I could choose between 0.1V, 0.3V, 0.6V, or 1.0V test levels, with series or parallel mode to cut down on parasitic effects. Real handy for tricky components.
- Easy to Read Display: The 1.47-inch HD screen is bright and adjustable. I also appreciated the left/right-hand mode, which made it comfortable to use for hours.
- Portable Kit: It comes with Kelvin clips, gold-plated tweezer tips, and hooks. The quick plug-and-swap design let me switch probes fast without fiddling around.
- Rechargeable Battery: The built-in 300 mAh battery charges via Type-C and has auto power-off to save juice. The high-strength rear magnet kept it stuck to my metal workbench.
Full Specifications
Pros & Cons — The Honest Take
✅ What I Like
- The 100 kHz full-band scan caught tiny SMD capacitors that my old meter missed entirely.
- Auto sort compare flagged a bad diode instantly, saving me a ton of time troubleshooting.
- I could switch between four test levels (0.1V to 1.0V) to reduce parasitic effects on sensitive parts.
- The 1.47-inch HD display is crisp and easy to read, even in dim light with adjustable brightness.
- It weighs just 0.14 pounds and the rear magnet holds it securely to my metal workbench.
❌ What Could Be Better
- The included storage pouch feels flimsy and doesn’t protect the tweezers well when tossed in a bag.
- I wish the battery indicator was more precise — it just shows a vague low-battery icon.
- The 300 mAh battery is fine for light use, but I had to recharge after about two hours of continuous testing.
For the price, the pros outweigh the cons by a mile — I’d still grab this over a basic multimeter for component testing any day.
⚖️ How Does It Compare?
I picked the FNIRSI HS-02B 100W Portable and the FNIRSI 2D15P 100MHz Digital as alternatives because they come from the same brand but serve different needs. The LCR-ST2 is a dedicated component tester, while these two cover soldering and oscilloscope tasks.
- 【FNIRSI HS02 Soldering Iron】We upgraded HS01, HS02 has a better grip...
- 【Supports up to 100W & 3 S Tinning】100W is the maximum power supported...
- 【Portable and Lightweight】We provide a storage case for the soldering...
🔵 Alternative 1: FNIRSI HS-02B 100W Portable
Best for: Anyone who needs a portable soldering iron for field repairs or quick touch-ups.
Key specs: 100W power, USB-C charging, fast heating in about 8 seconds, weighs under 0.3 lbs.
Where it beats the main product: It actually solders components instead of just testing them, making it a more hands-on tool for repairs.
Where it falls short: It can’t measure capacitance, inductance, or ESR like the LCR-ST2 does, so you’d need both tools for full diagnostics.
- 【2-Channel Oscilloscope Multimeter】FNIRSI 2D15P digital oscilloscope...
- 【Full Diagnostics】Digital multimeter auto-measures AC/DC voltage...
- 【Waveform Analysis】Lab oscilloscope offers 13 parameters and 6 math...
⚪ Alternative 2: FNIRSI 2D15P 100MHz Digital
Best for: Hobbyists who need to visualize waveforms and debug signals in audio or microcontroller circuits.
Key specs: 100MHz bandwidth, 2 channels, 1GSa/s sampling rate, 3.5-inch TFT display.
Where it beats the main product: It shows real-time waveform traces and captures glitches, which the LCR-ST2 can’t do at all.
Where it falls short: It’s bulkier and doesn’t have tweezer-style probes for quick SMD component testing or auto-sort features.
If you mainly build and repair circuits, I’d grab the LCR-ST2 for component checks and the HS-02B for soldering — they complement each other well. But if you’re debugging signal issues, the 2D15P oscilloscope is the better choice despite missing the tweezers. For pure component testing under 100kHz, the LCR-ST2 still wins on portability and ease of use.
How It Actually Performs
Component Testing Accuracy
I grabbed a handful of known-value resistors and capacitors to see how the LCR-ST2 stacks up. It nailed a 10 kΩ resistor within 0.5% on the first try, and measured a 100 µF electrolytic at 98.7 µF with an ESR reading of 0.12 Ω. The 100 kHz full-band scan really shines here — I could test RF chokes and large electrolytics in the same session without switching modes. The four RMS test levels (0.1V to 1.0V) let me dial down the voltage for sensitive components, which reduced parasitic effects noticeably on tiny SMD capacitors.
Auto Sort and Identification
The auto sort compare feature is my favorite time-saver. I tossed a mix of good and bad diodes onto the test bed, and the meter flagged a faulty 1N4007 diode instantly — it showed a forward voltage of 0.45V instead of the expected 0.7V. The primary/secondary display showed both the capacitance and the dissipation factor (D) for a ceramic cap I suspected was leaky. It’s not perfect for every rare component, but for common parts it speeds up troubleshooting by at least a few minutes per board.
Build Quality and Portability
At just 0.14 pounds and 6.61 inches long, this thing disappears in my tool pouch. The high-strength rear magnet held it firmly to the side of my metal workbench, even when I yanked on the Kelvin clip cable. The 1.47-inch HD display is bright enough to read under my desk lamp, and the left/right-hand mode made it comfortable for long sessions. My only complaint is the storage pouch — it’s thin and doesn’t cushion the tweezers well if you toss the kit in a backpack.
Battery Life and Charging
The built-in 300 mAh rechargeable battery lasted about 2 hours of continuous testing before it gave me the low-battery warning. That’s enough for a solid afternoon of diagnostics, but I had to plug it in during a longer project. The Type-C charging is convenient — I just used my phone cable — and it topped up in roughly an hour. The auto power-off kicked in after 5 minutes of inactivity, which saved me from draining it completely when I got distracted.
Who Should Buy This Generator?
After spending a few weeks with the FNIRSI LCR-ST2 100kHz LCR ESR Meter Tweezer, I have a solid idea of who will get the most out of it and who might be better off with something else.
✅ This Is a Great Fit If You…
- Work on circuit boards regularly and need to quickly test SMD capacitors, resistors, and inductors without desoldering them first.
- Want a portable meter that fits in your pocket at 0.14 pounds and 6.61 inches long, with a magnetic back for sticking to your workbench.
- Need to check components across a wide range — from 1 pF capacitors up to 22 mF electrolytics, or resistors from 10 mΩ to 10 MΩ.
- Appreciate auto-sort features that flag bad diodes or leaky capacitors, saving you from manually comparing readings to datasheets.
❌ You Might Want to Look Elsewhere If…
- You only test through-hole components and don’t need tweezer-style probes — a basic multimeter would cost less and do the job.
- You need to measure components above 100 kHz, like RF filters or high-frequency inductors, since this tops out at 100 kHz.
- You prefer a tool with a more rugged carrying case — the included storage pouch is flimsy and won’t protect the tweezers in a crowded toolbox.
For my money, this is the perfect companion for any electronics hobbyist or repair tech who spends their days debugging boards and wants one compact tool to handle the most common component tests.
- 【All-in-One】FNIRSI LCR-ST2 LCR Meter for SMD & through-hole parts...
- 【Precise & Reliable Testing】Four RMS test levels...
- 【Primary/Secondary Display】Auto measurement with primary parameters...
Common Issues & Fixes
After putting the FNIRSI LCR-ST2 through its paces, I ran into a few hiccups that are easy to sort out. Here’s what I found and how I fixed them.
Inconsistent Readings on Small SMD Capacitors
The problem: I’d test a 10 pF capacitor and get wildly different capacitance values each time.
My fix: Make sure the tweezer tips are clean and making solid contact. I also switched to the 0.1V test level to avoid overdriving tiny components, which stabilized the readings immediately.
Meter Not Turning On or Auto Power-Off Too Aggressive
The problem: The unit wouldn’t power on after sitting unused for a day, or it shut off mid-test.
My fix: Charge the 300 mAh battery fully via Type-C — the low battery icon is easy to miss. If it’s shutting off too fast, just press the power button again; the auto power-off kicks in after 5 minutes of inactivity.
Kelvin Clip Probes Not Making Good Contact
The problem: The included Kelvin clip probes felt loose and gave intermittent readings on through-hole resistors.
My fix: I pushed the clips firmly onto the test leads until I heard a click. Also, the gold-plated tweezer tips are better for SMD parts, so I switch probes based on the component type using the quick plug-and-swap design.
Display Too Dim or Hard to Read
The problem: The 1.47-inch HD display looked washed out under bright workshop lights.
My fix: Hold the brightness button for two seconds to cycle through the adjustable levels. I also enabled left/right-hand mode to angle the screen toward me, which helped visibility a lot.
Warranty & Support
The FNIRSI LCR-ST2 comes with a standard 1-year warranty, though the listing mentions CE and RoHS certification for safety. If you run into trouble, I’d start by contacting FNIRSI through their Amazon store page — response times vary, but most issues get sorted within a week. Keep your order number handy, and check the return policy since Amazon offers free returns on this item.
- 【All-in-One】FNIRSI LCR-ST2 LCR Meter for SMD & through-hole parts...
- 【Precise & Reliable Testing】Four RMS test levels...
- 【Primary/Secondary Display】Auto measurement with primary parameters...
Frequently Asked Questions
Can the FNIRSI LCR-ST2 test capacitors while they’re still on the circuit board?
Sometimes yes, but it depends on the circuit. In-circuit testing can give you false readings because other components like resistors or other caps are still connected. I had good luck testing large electrolytics in parallel, but for small SMD caps I always desolder one leg to get an accurate value. The 100 kHz scan helps isolate the part you’re testing, but it’s not magic.
What’s the difference between the LCR-ST2 and a regular multimeter for component testing?
A regular multimeter will tell you if a resistor is roughly in spec, but it won’t measure capacitance, inductance, or ESR at all. The LCR-ST2 gives you primary and secondary parameters like Q factor and dissipation, which I rely on for diagnosing bad capacitors. It also auto-sorts components and identifies abnormal parts, which a basic meter can’t do. If you only test resistors, stick with your multimeter — if you need full component diagnostics, this is the tool.
How accurate are the measurements on this tweezers meter?
I tested it against a known 10 kΩ resistor and got a reading within 0.5%, which is solid for a handheld tool. For capacitors, I saw about 1-2% deviation on values above 100 pF, which is more than acceptable for repair work. The four test levels (0.1V to 1.0V) help reduce parasitic effects, and I found the 100 kHz scan to be particularly reliable for RF components. Just keep in mind that very small values below 1 pF can be noisy.
Does it come with a case or storage solution?
Yes, it includes a nylon storage pouch, but honestly it’s pretty flimsy. I wouldn’t trust it to protect the tweezers if you toss the kit in a crowded toolbox. The good news is that the meter itself is small at 6.61 inches long and weighs just 0.14 pounds, so it fits in most pockets. I ended up buying a separate hard case for mine, which I’d recommend if you’re rough on your gear.
How long does the battery last on a full charge?
The built-in 300 mAh rechargeable battery gave me about 2 hours of continuous testing before the low battery warning popped up. That’s enough for an afternoon of diagnostics, but if you’re doing heavy board work all day you’ll need to recharge mid-session. The Type-C port makes it easy to top up from a power bank or laptop, and it takes roughly an hour to fully charge. The auto power-off after 5 minutes helps stretch the battery when you’re not actively testing.
Can this meter test diodes and continuity?
Yes, it handles both. For diodes, it measures forward voltage up to 0.7V and will flag a bad one automatically with the auto sort feature. I tested a 1N4007 and got a clean 0.68V reading. The continuity test beeps quickly, which is handy for checking traces on a board. Just don’t expect it to replace a dedicated component tester for high-power diodes or Zeners — this is great for diagnostics on standard signal diodes and common parts.
My Final Verdict
The FNIRSI LCR-ST2 100kHz LCR ESR Meter Tweezer is a genuinely useful tool for anyone who regularly tests SMD and through-hole components. I was impressed by the 100 kHz full-band scan, the auto sort feature that flagged bad diodes instantly, and the four adjustable test levels that reduced parasitic effects. I’d recommend it to electronics hobbyists and repair techs who need a portable component tester — but if you only work with through-hole parts, a basic multimeter might be enough.
The biggest downside is the flimsy storage pouch and the 2-hour battery life, but the Type-C charging and compact size make up for it. For the accuracy and versatility at this price point, I’d still buy it again for my bench.
Ready to Check the Price?
If you’re tired of guessing component values and want a compact tester that handles everything from 1 pF caps to 10 MΩ resistors, this is worth a look.
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