USB Tester 4-28V 7A LCD USB A&C Voltage Current Power Tester

In this review the FNIRSI USB tester is examined for hobbyists, technicians and anyone who frequently tests chargers, cables and power banks; its single biggest reason to buy is its combination of multiport physical connectors with protocol detection and app support, making it a practical troubleshooting tool. The tester offers a clear 2.0' TFT LCD and integrated USB-A, Micro-USB and Type-C ports, and is useful when you need to verify voltage, current, power, capacity and fast charge protocol behavior without carrying multiple adapters.

Key Features

• Multi-port design: Integrated USB-A, Micro-USB and Type-C ports let the tester connect directly to a wide range of chargers and cables without extra adapters.
• Protocol detection: Automatic support for QC2.0/QC3.0, PD2.0/3.0, FCP/SCP, AFC, VOOC/WARP and Super VOOC triggers makes identifying fast charge behavior straightforward.
• Accurate measurement: External 16-bit ADC and a PD physical protocol chip provide detailed readings of voltage, current, power and capacity for reliable diagnostics.
• Waveform and ripple views: Low-speed waveform drawing and ripple measurement with adjustable sampling rates let users inspect transient behavior and noise on power lines.
• App connectivity: Bluetooth app integration and onboard features such as temperature and PD monitoring allow logging and remote observation from a mobile device.
• Cable and accessory tests: E-Marker and DASH cable reading plus differential wire resistance measurement make it useful for cable verification and quality checks.

Who It's For

The FNIRSI USB tester is ideal for electronics hobbyists, field technicians and mobile repairers who need a compact, all-in-one meter to validate chargers, power banks and cable behavior. Its combination of protocol triggering and recording is particularly useful for anyone diagnosing charging faults or confirming fast charge compatibility.

Users who want the simplest possible plug-and-play experience with printed documentation may be disappointed, since the device relies on digital manuals via QR code and the app. If you only need a basic USB voltage reader without protocol testing or advanced logging, a simpler meter may be a better, lower-cost choice.

Pros & Cons

Pros

• Comprehensive protocol detection that covers PD, QC, VOOC and other fast charge standards for accurate compatibility checks.
• Integrated sockets and clear 2.0' TFT display make field use convenient without extra dongles.
• Detailed measurements including capacity, D+/D- voltage, ripple and waveform drawing support deeper diagnostics.
• App software and firmware update path allow logging and future improvements.

Cons

• Manual is digital only and not printed, which some users find inconvenient for first-time setup.
• Device complexity means a learning curve for users who only need simple voltage readings.

Specifications

Display	2.0' TFT LCD
Input/Output Ports	USB-A, Micro-USB, Type-C
Measured Parameters	Voltage, Current, Power, Resistance, Capacity, D+/D- voltage
Protocol Support	PD2.0/3.0, QC2.0/3.0, FCP/SCP, AFC, VOOC/WARP, Super VOOC
ADC	External 16-bit ADC
Sampling Rates	Low-speed 2 sps-100 sps; ripple up to 4 M sps
Additional Features	E-Marker/DASH reading, temperature measurement, app connectivity

Our Verdict

The FNIRSI USB tester is a versatile, well-built tool for anyone who needs to test charging behavior, cable quality and protocol compatibility; it packs advanced measurement and automatic fast charge detection into a compact unit that offers strong value for technicians and enthusiasts. Those wanting a simple plug-in voltmeter should consider a basic alternative, but for diagnostic depth and protocol support this tester is hard to match at the price.

Frequently Asked Questions

Does it detect fast charge protocols automatically?
Yes, automatic monitoring supports QC2.0/QC3.0, PD2.0/3.0, FCP/SCP, AFC, VOOC/WARP and Super VOOC triggers.

Can it read cable E-Marker chips?
Yes, the tester can read E-Marker and DASH cable data to help verify cable capabilities.

Is there a printed manual included?
No, the device uses a QR code for access to the manual, firmware and app downloads to reduce paper use.