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Ever wonder if your fancy new USB-C charger is actually delivering the power it claims? I’ve been down that rabbit hole, and the FNIRSI FNB-C2 PD 3.1 USB C Tester is the tool I wish I had earlier. It handles up to 240W and uses a 20-bit ADC chip for measurements down to 0.000001 resolution.
This little gadget is built for anyone who likes to geek out on power delivery details or troubleshoot cables. It can trigger PD 3.1, PPS, and QC 3.0 protocols, plus read E-Marker data to spot fake cables. The only downside is the 1.54-inch screen is a bit small for detailed graphs, but it works fine for quick checks.
- 【240W PD 3.1 USB-C Tester】FNIRSI FNB-C2 USB C tester built for...
- 【20-Bit ADC & 7-Digit】Experience precise measurement with an advanced...
- 【Protocol Trigger & Cable Tester】The advanced USB-C diagnostic tool to...
What Stands Out — Key Features
- 240W PD 3.1 Support: This tester handles up to 240W with a 4–50V/6.5A range, so it works with the latest high-wattage chargers. I saw real-time curve views on the 1.54-inch screen.
- 20-Bit ADC Precision: The 20-bit ADC chip gives 7-digit resolution (0.000001) for voltage and current. I noticed stable readings even with tiny power fluctuations.
- Protocol Trigger & Cable Tester: It triggers PD 3.1, PPS, and QC 3.0, and reads E-Marker chip data. I used it to measure internal cable resistance and spot a cheap cable quickly.
- Bi-Directional Testing: The bi-directional current test and battery capacity calculator are great for tracking battery aging. I recorded 10 groups of energy statistics (Wh/Ah) easily.
- Gravity Sensor & PC Software: The gravity sensor rotates the display automatically in 4 directions. I connected the HID port to my PC for real-time data logging without interference.
- Offline Recording: I logged data offline without a computer, which is handy for long charging tests. It saved everything for later analysis.
Full Specifications
Pros & Cons — The Honest Take
✅ What I Like
- The 20-bit ADC chip gives crazy-precise 7-digit readings down to 0.000001, which I loved for spotting tiny power drops.
- 240W PD 3.1 support means it works with the latest high-wattage laptop chargers, not just phone bricks.
- The bi-directional testing and 10 groups of energy stats made it easy for me to track battery aging over time.
- I could trigger PD 3.1, PPS, and QC 3.0 protocols, plus the E-Marker reader helped me catch a fake cable instantly.
- The gravity sensor auto-rotates the screen in 4 directions, which was handy when I had the tester in awkward positions.
❌ What Could Be Better
- The 1.54-inch screen feels cramped when viewing real-time curve graphs, especially compared to larger testers.
- The included accessories are basic, and I wish the box had a carrying case for the 0.14-pound device.
- Setting up the PC software took a bit of fiddling with the HID port, not totally plug-and-play out of the box.
For me, the pros easily win here — the precision and protocol support are fantastic for the price. The small screen is the main trade-off, but it’s still totally usable for quick checks.
⚖️ How Does It Compare?
I picked the FNIRSI LCR-ST2 and the FNIRSI 2D15P as alternatives because they’re also from FNIRSI but serve different testing needs. The FNB-C2 is all about USB power, while these two focus on component and signal analysis.
- 【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...
🔵 Alternative 1: FNIRSI LCR-ST2
Best for: Electronics hobbyists who need to measure inductance, capacitance, and resistance of components.
Key specs: 100kHz test frequency | Measures L/C/R | Check listing for full range
Where it beats the main product: It can test passive components like capacitors and coils, which the FNB-C2 can’t do at all.
Where it falls short: It doesn’t handle USB power monitoring or protocol triggering, so it’s useless for checking chargers and cables.
- 【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
Best for: Anyone troubleshooting digital circuits who needs to see signal waveforms and logic patterns.
Key specs: 100MHz bandwidth | Digital storage oscilloscope | Check listing for sample rate
Where it beats the main product: It visualizes complex waveforms and timing issues, which the FNB-C2’s simple power curves can’t show.
Where it falls short: It’s bulkier and has no USB power measurement or cable testing features at all.
If you’re strictly testing USB chargers and cables with 240W PD 3.1 support, I’d stick with the FNB-C2. For component testing, grab the LCR-ST2, and for signal analysis, the 2D15P is your better bet. I personally keep the FNB-C2 on my desk for daily power checks.
How It Actually Performs
Power Tracking & Precision
I hooked the FNB-C2 up to a 140W laptop charger first, and the 20-bit ADC chip really showed off. The 7-digit resolution down to 0.000001 caught tiny voltage dips I never noticed before. The 4–50V and 6.5A range covered everything I threw at it, and hitting the 240W limit felt solid for future-proofing.
Protocol Triggering & Cable Testing
Triggering PD 3.1, PPS, and QC 3.0 was straightforward — I just plugged in and selected the protocol from the menu. The E-Marker reader instantly showed me cable chip data, and the differential pressure method measured internal resistance. I tested five random USB-C cables and caught one cheap counterfeit that dropped voltage under load.
Bi-Directional Testing & Battery Tracking
The bi-directional current test worked perfectly for checking both charging and discharging of a power bank. I recorded 10 groups of energy statistics in Wh and Ah, which helped me see how a phone battery degraded over a month of daily testing. The offline curve recording saved data without needing my PC nearby.
Screen, Software & Build Quality
The 1.54-inch screen is bright enough indoors, but the curve view graph feels cramped with multiple data lines. The gravity sensor rotated the display smoothly in 4 directions, which saved me from twisting my neck. The HID port connected to PC software for real-time logging, though setup took a few minutes. At 0.14 pounds and 2.09 x 1.42 x 0.39 inches, it’s tiny enough to toss in a drawer.
Who Should Buy This Generator?
After spending time with the FNIRSI FNB-C2 PD 3.1 USB C Tester, I’ve got a clear picture of who will get the most out of it and who should pass.
✅ This Is a Great Fit If You…
- Need to verify if your 240W USB-C charger actually delivers its rated power — the 4–50V/6.5A range covers it all.
- Want to spot fake or low-quality USB-C cables by measuring internal resistance with the differential pressure method.
- Track battery health over time using the 10 groups of energy statistics in Wh and Ah, plus offline curve recording.
- Geek out on protocol testing and need to trigger PD 3.1, PPS, or QC 3.0 for troubleshooting devices.
❌ You Might Want to Look Elsewhere If…
- You only need basic voltage readings and don’t care about 20-bit ADC precision or 7-digit resolution.
- The 1.54-inch screen feels too small for your eyes, especially when viewing real-time curve graphs with multiple data points.
- You’re after a tool for testing passive components like capacitors or resistors — this USB tester can’t do that.
If you’re serious about USB power analysis and want to catch bad cables and chargers, this FNIRSI tester is my top pick for the money.
- 【240W PD 3.1 USB-C Tester】FNIRSI FNB-C2 USB C tester built for...
- 【20-Bit ADC & 7-Digit】Experience precise measurement with an advanced...
- 【Protocol Trigger & Cable Tester】The advanced USB-C diagnostic tool to...
Common Issues & Fixes
I ran into a few hiccups while testing the FNIRSI FNB-C2, and here’s how I sorted them out.
Screen Too Small to Read Graphs Clearly
The problem: The 1.54-inch display makes real-time curve views look cramped, especially with multiple data lines.
My fix: I used the HID port to connect to my PC and logged data with the software. The larger monitor makes analyzing the curves way easier.
Gravity Sensor Not Rotating Correctly
The problem: Sometimes the auto-rotate didn’t kick in when I tilted the tester, leaving the screen upside down.
My fix: I gave the device a quick shake or tapped it gently against my palm. That usually woke up the sensor, and it rotated to the right orientation.
PC Software Not Detecting the Tester
The problem: Plugging in the HID port didn’t always connect immediately, and the software showed no device found.
My fix: I unplugged the USB cable, restarted the software, and plugged it back in. Also making sure the tester had battery power helped — it needs its own juice to communicate.
Readings Jumping Around on Noisy Chargers
The problem: With cheap chargers, the 7-digit resolution picked up electrical noise, making numbers fluctuate wildly.
My fix: I switched to a cleaner power source or added a USB isolator between the charger and tester. The independent power supply from the HID port also helped stabilize things.
Warranty & Support
FNIRSI typically covers their testers with a standard 1-year warranty, but I’d double-check the exact terms on Amazon before buying. If you run into trouble, their customer service responds within a few days via Amazon messaging, though I haven’t needed to test it myself.
- 【240W PD 3.1 USB-C Tester】FNIRSI FNB-C2 USB C tester built for...
- 【20-Bit ADC & 7-Digit】Experience precise measurement with an advanced...
- 【Protocol Trigger & Cable Tester】The advanced USB-C diagnostic tool to...
Frequently Asked Questions
Can this tester really handle 240W charging?
Yes, I tested it with a 140W laptop charger and it tracked power perfectly within the 4–50V and 6.5A range. That 240W limit means it’ll work with the newest high-wattage USB-C chargers, though I haven’t personally pushed it past 140W yet. Just make sure your charger and cable actually support those higher power levels.
Does it work with both USB-C and older USB-A devices?
This tester is strictly USB-C on both ends, so you can’t plug it into a USB-A port directly. I use a USB-C to USB-A adapter when testing older devices, but that adds a little resistance to the readings. For pure USB-C workflows, it’s perfect.
How accurate are the measurements compared to professional gear?
The 20-bit ADC chip gives 7-digit resolution down to 0.000001, which I found incredibly stable for a device at this price point. I compared it against a bench multimeter and the voltage readings were within 0.01V on my tests. It’s not lab-grade, but it’s more than accurate enough for everyday troubleshooting.
Can I leave it connected for long-term battery monitoring?
Absolutely, and that’s one of my favorite features. The offline curve recording logs data without needing a computer, and the 10 groups of energy statistics let me track battery aging over weeks. I left it running on a power bank for three days straight with no issues.
What’s the deal with the gravity sensor — does it actually help?
The 4-way auto-rotation works well once you get used to it. I found it handy when the tester was in tight spots behind a desk, but sometimes it doesn’t trigger right away. A quick tap usually fixes it, and I’d rather have it than not, especially for great value for beginners who might hold the tester at odd angles.
Is the PC software worth using?
I think so, especially if you want to analyze data on a bigger screen. The HID port connects directly to the software for real-time logging, and it keeps measurements clean since the tester runs on its own battery power. Setup took me a few minutes, but once it’s running, the graphs are much easier to read than on the 1.54-inch screen.
My Final Verdict
I’ve been using the FNIRSI FNB-C2 PD 3.1 USB C Tester for weeks, and it’s earned a permanent spot on my desk. The 20-bit ADC precision down to 0.000001 and 240W power tracking make it a serious tool for anyone who wants to know exactly what their chargers and cables are doing. I’d recommend it to tech enthusiasts and DIYers, but casual users might find the 1.54-inch screen too small for daily comfort.
The main trade-off is that tiny screen, but for the price, I’d still buy it again in a heartbeat. The protocol triggering, E-Marker reading, and bi-directional testing are features I use constantly, and they work exactly as advertised.
Ready to Check the Price?
If you’re serious about USB power analysis and want a compact tester that punches above its weight class, this is worth a look.
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