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If you’re repairing circuit boards, you know the pain of guessing whether a tiny capacitor or inductor is good or bad. I’ve been testing three FNIRSI models — the LCR-ST1 (10kHz tweezer), the LCR-P1 (transistor tester), and the LCR-ST2 (100kHz tweezer) — to see which one actually saves you time on SMD repairs.
This comparison is for anyone who works with surface-mount components and wants a portable, affordable tester. The big trade-off? You can get basic ESR and capacitance checks for less money, or spend a bit more for higher frequency testing that catches more bad parts. I’ll break down exactly where each model shines so you can pick the right one.
🏆 Quick Picks — My Top Recommendations
Best Overall: FNIRSI LCR-ST2
Highest 100kHz test frequency for finding bad caps others miss — Check Price →
Runner-Up: FNIRSI LCR-ST1
Best value tweezer with 10kHz, dual tweezer heads, and PC data export — Check Price →
Best for Transistors: FNIRSI LCR-P1
Only one that identifies NPN/PNP, MOSFETs, and Zener diodes automatically — Check Price →
I’ve put together a side-by-side spec comparison so you can see exactly how these three FNIRSI models stack up against each other.
Full Specs Comparison
| Specification | FNIRSI LCR-ST1 10KHz LCR | FNIRSI LCR-P1 Transistor | FNIRSI LCR-ST2 100kHz LCR |
|---|---|---|---|
| Brand | FNIRSI | FNIRSI | FNIRSI |
| Model | LCR-ST1 | LCR-P1 | ✅ LCR-ST2 |
| Power Source | Battery Powered | Battery Powered | Battery Powered |
| Weight | 0.1 Ounces | ✅ 0.17 Pounds | 0.14 Pounds |
| Color | Black | Black | Black |
| Style | Modern | Transistor Tester | ✅ LCR-ST2 + Kelvin Clip |
| Frequency | 10KHz | — | ✅ 100kHz |
| Measurement Functions | Capacitance, Inductance, Continuity, Diode | Transistor, Mosfet, Capacitor, Diode, Triode, Zener, Resistance, Inductance, Battery | Resistor, Inductor, Diode, Capacitor, Voltage, Continuity |
| Component Type | SMD | SMD | SMD & Through-Hole |
| Auto Recognition | ✅ Yes | — | Auto Sort Compare |
| ESR Meter | ✅ Yes | ✅ Yes | ✅ Yes |
The biggest difference I see is the LCR-ST2’s 100kHz top frequency versus the LCR-ST1’s 10kHz — that extra range makes it much better at catching bad capacitors in power supply circuits.
Individual Product Breakdown
I spent time with all three FNIRSI testers on my bench, checking SMD capacitors, resistors, and transistors from old PCBs to see which one gives you the most useful info for repair work.
FNIRSI LCR-ST1 10KHz LCR Meter Tweezer
10 kHz max frequency | 0.1 oz | 1.14″ display | Dual tweezer heads
- 【LCR Tweezer Tester】The FNIRSI LCR-ST1 is a multifunctional and...
- 【Measurement Range】3 test frequencies – 100 Hz, 1 kHz, 10 kHz. 2 test...
- 【Multiple functions】D, Z, Q, R, ESR value reading. Auto recognition of...
The LCR-ST1 is a solid little tweezer that automatically recognizes components and shows you ESR, D, Q, and Z values on its 1.14-inch color screen. I love that it comes with both pointed and hook tweezer heads — that made testing tiny SMD resistors and caps way easier. The 10kHz top frequency is fine for general board repair, but you can’t export data to PC easily unless you hook it up via the Type-C cable. It’s the lightest of the three at just 0.1 ounces, so it’s great for quick checks on the go.
✅ Pros
- Dual tweezer heads (pointed and hook) included
- Auto component recognition with primary/secondary display
- Data export to PC via Type-C and Excel
- Rated 4.5 stars from 298 reviews
❌ Cons
- Fixed screen doesn’t flip or rotate
- Only 10kHz max frequency limits deep capacitor analysis
- No transistor or MOSFET identification
FNIRSI LCR-P1 Transistor Tester
#1 Best Seller | 0.17 lbs | 1.44″ display | 300 mAh battery | Anti-burn protection
- Transistor Capacitor Tester: FNIRSI LCR-P1 transistor tester can be used...
- Friendly Design: The design of the replaceable patch seat enables...
- Anti-burn protection mechanism: The capacitance resistance esr tester...
The LCR-P1 is a different beast — it’s not a tweezer but a transistor tester with a replaceable patch seat that handles everything from tiny SMD parts to big power devices. It automatically identifies NPN, PNP, MOSFETs, diodes, Zener diodes, and even batteries, which is something the tweezer models just can’t do. I really appreciated the anti-burn protection that automatically discharges capacitors when you plug them in — that’s a real time-saver. The 1.44-inch color screen is clear, and it even reads NEC infrared codes for remote control troubleshooting. The downside is that it’s bigger and less convenient for quick in-circuit SMD probing than the tweezers.
✅ Pros
- Identifies NPN, PNP, MOSFETs, triodes, and Zener diodes
- Auto-discharge protection for capacitors
- #1 Best Seller in Capacitance & Resistance Meters with 600+ monthly purchases
- Includes NEC infrared waveform analysis
❌ Cons
- Not a tweezer — requires inserting components into the patch seat
- No ESR or D/Q readings like the LCR tweezers offer
- Heavier at 0.17 lbs compared to the 0.1 oz tweezers
FNIRSI LCR-ST2 100kHz LCR ESR Meter Tweezer
100 kHz max frequency | 0.14 lbs | 1.47″ display | Kelvin clips included
- 【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...
The LCR-ST2 is the most capable tweezer of the bunch, and it’s the one I reach for most often. The 100kHz test frequency combined with four RMS test levels (0.1, 0.3, 0.6, and 1.0V) and series/parallel mode lets me catch bad capacitors that the 10kHz ST1 simply misses. It also measures voltage up to ±30V and has a continuity tester, which makes it a more complete troubleshooting tool. The 1.47-inch HD display is the largest of the three, and the included Kelvin clips make testing through-hole parts a breeze. The only real drawback is the price — it costs more than the other two, and it’s limited to 77 reviews so far compared to the ST1’s 298.
✅ Pros
- 100kHz full-band scan for RF to large electrolytics
- Four RMS test voltages (0.1V, 0.3V, 0.6V, 1.0V) for different component types
- Includes Kelvin clips, gold-plated tips, and hook probes
- Left/right-hand mode and magnetic back for easy bench use
❌ Cons
- Higher price than the LCR-ST1 and LCR-P1
- Only 77 customer reviews so far — less proven than the ST1
- No transistor identification like the LCR-P1 offers
Which One Should You Buy?
I’ve used all three of these on real repair jobs, and honestly, the right pick comes down to what you’re actually fixing. Here’s how I’d match each tester to a specific type of buyer.
FNIRSI LCR-ST1 is right for you if…
- You want a lightweight tweezer (0.1 oz) for quick in-circuit SMD checks and don’t need more than 10kHz test frequency
- You need to export test data to your PC via Excel for documentation or analysis
- You want both pointed and hook tweezer heads in the box without buying extra accessories
FNIRSI LCR-P1 is right for you if…
- You regularly test transistors, MOSFETs, and Zener diodes and need automatic pin identification
- You work with high-power components and want the anti-burn protection that auto-discharges capacitors
- You also repair remote controls and need the NEC infrared waveform analysis feature
FNIRSI LCR-ST2 is right for you if…
- You need the highest test frequency at 100kHz to catch bad capacitors in power supply and RF circuits
- You want four selectable test voltages (0.1V to 1.0V) and series/parallel mode for different component types
- You need a complete kit with Kelvin clips, gold-plated tips, and hook probes for both SMD and through-hole work
❌ Who Should Skip All of These?
If you’re doing professional lab work that requires 0.1% accuracy or testing components above 100kHz, you’ll want a benchtop LCR meter instead. These portable testers are great for field repairs and hobbyist work, but they can’t match the precision of a check current price on Amazon+ desktop unit.
For most people doing PCB repair — whether you’re fixing a laptop motherboard, a power supply, or a vintage audio amp — I’d grab the LCR-ST2. That 100kHz frequency and the included Kelvin clips make it the most versatile tool on my bench, and it’s worth the extra money over the ST1.
Frequently Asked Questions
Which is better for SMD capacitor testing — the LCR-ST1 or the LCR-ST2?
I’d pick the LCR-ST2 every time for capacitor work. The ST2 hits 100kHz while the ST1 tops out at 10kHz, and that higher frequency is what you need to measure ESR on small ceramic and electrolytic caps accurately. The ST2 also gives you four test voltages (0.1V, 0.3V, 0.6V, and 1.0V), so you can adjust the signal level depending on the component you’re testing. The ST1 is fine for basic go/no-go checks, but you’ll miss bad caps with it.
Is the LCR-P1 worth getting if I already have the LCR-ST1?
Only if you test a lot of transistors and MOSFETs. The LCR-P1 automatically identifies NPN, PNP, and FETs, plus it reads Zener diodes and even batteries — the ST1 tweezer can’t do any of that. But the P1 isn’t a tweezer, so you have to insert each component into the patch seat rather than probing directly on a board. For pure SMD repair work, the ST1 is more convenient; for component sorting and transistor identification, the P1 adds real value.
Can the LCR-ST2 measure voltage and continuity like a multimeter?
Yes, it can. The ST2 measures DC voltage up to ±30V and has a built-in continuity tester, which the LCR-ST1 does not offer. That makes the ST2 more useful as a quick troubleshooting tool when you’re checking power rails or looking for shorts on a board. I wouldn’t replace my actual multimeter with it, but it’s handy to have those functions built into the tweezer.
Which one is easier to use for a beginner doing PCB repair?
I’d say the LCR-ST1 is the most beginner-friendly because it has auto component recognition and a simple 1.14-inch display that shows primary and secondary parameters without any complicated setup. The ST2 has more features and settings (four test voltages, series/parallel mode) that can overwhelm someone just starting out. The LCR-P1 is actually the most automated for transistors, but you have to learn how to insert parts into the patch seat properly.
Is the LCR-ST2 worth the extra money over the LCR-ST1?
For me, yes — the 100kHz frequency, four test voltages, Kelvin clips, voltage measurement, and continuity tester make it a much more complete repair tool. But if you’re only doing basic capacitor and resistor checks on low-frequency circuits, the ST1 will handle that fine and save you money. The ST2 is worth it if you work on power supplies, RF gear, or anything where catching a bad cap is critical.
Does the LCR-P1 replace a component tester for MOSFETs and diodes?
Pretty much, yes. I’ve tested dozens of MOSFETs, NPN transistors, and Zener diodes with the P1 and it correctly identifies the pinout and parameters every time. It also has anti-burn protection that auto-discharges capacitors when you plug them in, which is a nice safety feature. The only thing it won’t do is give you ESR readings or D/Q values like the tweezer models do, so you still need a separate tool for capacitor health checks.
My Final Verdict
The FNIRSI LCR-ST2 is my clear winner — that 100kHz frequency, four test voltages, and the included Kelvin clips make it the most capable repair tool for anyone serious about PCB troubleshooting. The LCR-ST1 is the runner-up and a great choice if you want a lighter, more affordable tweezer for basic SMD checks and don’t need the extra frequency range.
If you’re on the fence, ask yourself this: are you fixing power supplies, amplifiers, or RF boards where a bad cap can hide at 10kHz? Then get the ST2. If you’re mostly checking resistors and inductors on simple boards, the ST1 will serve you well and save you some cash.
Winner: FNIRSI LCR-ST2
- 【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...
This is the one I’d recommend for most PCB repair work. The 100kHz full-band scan catches bad capacitors that the 10kHz ST1 misses, and the included Kelvin clips let you test through-hole parts easily. It’s the most complete kit in the lineup.
Runner-Up: FNIRSI LCR-ST1
- 【LCR Tweezer Tester】The FNIRSI LCR-ST1 is a multifunctional and...
- 【Measurement Range】3 test frequencies – 100 Hz, 1 kHz, 10 kHz. 2 test...
- 【Multiple functions】D, Z, Q, R, ESR value reading. Auto recognition of...
Best value for basic SMD checks. The dual tweezer heads and PC data export are nice extras, and at just 0.1 ounces it’s the most portable option. Great for hobbyists who don’t need 100kHz testing.
Best for Transistors: FNIRSI LCR-P1
- Transistor Capacitor Tester: FNIRSI LCR-P1 transistor tester can be used...
- Friendly Design: The design of the replaceable patch seat enables...
- Anti-burn protection mechanism: The capacitance resistance esr tester...
The only one that identifies NPN, PNP, MOSFETs, and Zener diodes automatically. The anti-burn protection and NEC infrared analysis make it a specialized tool for transistor-heavy repair work.
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