1. Introduction
The FNIRSI LCR-ST2 is a compact, high-precision smart tweezer LCR meter designed for efficient testing of electronic components. It supports both tweezer and Kelvin-clip testing modes, making it versatile for various component sizes and types. This device accurately measures resistance, capacitance, inductance, diodes, and voltage up to ±30V. Equipped with a 1.47-inch HD display and multiple test frequencies, it offers comprehensive analysis capabilities including full-band sweep, intelligent sorting, and dual series/parallel equivalent comparison. Its portable design, magnetic attachment, and long-lasting battery make it an ideal tool for professionals and hobbyists in circuit board repair, electronics R&D, DIY projects, and production testing.
2. Key Features
- Wide Range Component Measurement: Accurately measures resistance (10 mΩ–10 MΩ), capacitance (1 pF–22 mF), inductance (1 μH–10 H), diode (≤0.7 V), and voltage (±30 V).
- Comprehensive Electrical Parameters: Provides D/Q/Z/X/θ/ESR readings for full component characterization.
- Five Selectable Test Frequencies: Offers professional testing at 100Hz, 120Hz, 1kHz, 10kHz, and 100kHz.
- Four RMS Test Levels: Adjustable excitation levels (0.1V / 0.3V / 0.6V / 1.0V) for optimized measurement stability.
- Dual Series/Parallel Equivalent Comparison: Simultaneously displays series and parallel equivalent values to minimize parasitic interference.
- Full-Band Sweep Mode (100Hz–100kHz): Fast multi-frequency analysis for detailed component frequency response.
- Intelligent Sorting with Tolerance Grading: Automatic component evaluation based on preset nominal values and tolerances for rapid batch testing.
- Dual-Form Testing: Tweezer Tips + Kelvin Clip: Straight and curved tweezer tips for small components, Kelvin clip for larger or through-hole components.
- Smart Recognition & Display Functions: Automatic R/C/L component recognition, dual-parameter display, HOLD/Max/Min, and adjustable system settings.
- Auto-Rotate Orientation: Hand-sensing screen rotation for left-handed and right-handed use.
- Portable Magnetic Design: Magnetic attachment for easy storage and handling.
- 1.47" HD Color Display: Clear, high-contrast visualization of measurement data.
- Long Battery Life & Type-C Charging: 300mAh lithium battery with Type-C charging, providing up to ~3 hours of continuous operation.
3. Package Contents
Please check the package contents upon receipt. The standard package includes:
- FNIRSI LCR-ST2 Tweezer Meter
- Storage Bag
- Curved Tip (pair)
- Shorting Plate
- Data Cable (Type-C)
The "Plus Option" package additionally includes:
- Kelvin Test Clip
4. Specifications
| Parameter | Value |
|---|---|
| Model | LCR-ST2 |
| Brand Name | FNIRSI |
| Display Type | Digital Display (1.47-inch HD color screen) |
| Operating Mode | Auto Range |
| Standby Time | ≈3H |
| Dimensions | 31 x 170.7 x 20.3mm |
| Weight | ≈60.8g |
| Battery | 300mAh lithium battery (Included) |
| Charging Port | Type-C |
| Operating Temperature | 0℃ ~ 50℃ (Humidity ≤ 75%) |
| Storage Temperature | -20℃ ~ 60℃ (Humidity ≤ 75%) |
| Auto Power-off | Never / 5 / 15 / 30 min |
| Language | English / Chinese |
| DIY Supplies | Electrical |
| Certification | CE |
Measurement Ranges and Accuracy:
| Capacitance Range | 100Hz/120Hz | 1KHz | 10KHz | 100KHz |
|---|---|---|---|---|
| 1mF‒22mF | 5% ± 3 digits | 5% ± 3 digits | / | / |
| 1µF‒1mF | 2% ± 3 digits | 2% ± 3 digits | 2% ± 3 digits | 5% ± 3 digits |
| 1nF‒1µF | 2% ± 3 digits | 0.5% ± 3 digits | 0.5% ± 3 digits | 5% ± 3 digits |
| 1pF‒1nF | / | 2% ± 3 digits | 2% ± 3 digits | 5% ± 3 digits |
| Inductance Range | 100Hz/120Hz | 1KHz | 10KHz | 100KHz |
|---|---|---|---|---|
| 1H‒10H | 5% ± 3 digits | 5% ± 3 digits | / | / |
| 1mH‒1H | 2% ± 3 digits | 2% ± 3 digits | / | / |
| 10µH‒1mH | 2% ± 3 digits | 0.5% ± 3 digits | 0.5% ± 3 digits | 5% ± 3 digits |
| 1µH‒10µH | / | 2% ± 3 digits | 2% ± 3 digits | 5% ± 3 digits |
| Resistance Range | 100Hz/120Hz | 1KHz | 10KHz | 100KHz |
|---|---|---|---|---|
| 1MΩ‒10MΩ | 5% ± 3 digits | 5% ± 3 digits | / | / |
| 1kΩ‒1MΩ | 1% ± 3 digits | 0.5% ± 3 digits | 1% ± 3 digits | / |
| 1Ω‒1kΩ | 1% ± 3 digits | 0.5% ± 3 digits | 1% ± 3 digits | 5% ± 3 digits |
| 10mΩ‒1Ω | 2% ± 3 digits | 2% ± 3 digits | 2% ± 3 digits | 5% ± 3 digits |
| Diode & Voltage | Value |
|---|---|
| Diode Forward Voltage Detection | ≤0.7V |
| Voltage Range | ±30V |
5. Setup Guide
5.1 Charging the Device
The LCR-ST2 is powered by a built-in 300mAh lithium battery. Before first use, or when the battery indicator is low, charge the device using the provided Type-C USB cable and a standard USB power adapter (not included).
- Connect the Type-C end of the data cable to the charging port on the LCR-ST2.
- Connect the USB-A end to a power source.
- The display will indicate charging status.
5.2 Attaching Tweezer Tips and Kelvin Clips
The LCR-ST2 supports two primary testing methods: integrated tweezer tips for SMD components and external Kelvin clips for larger or through-hole components.
- Tweezer Tips: The device comes with straight gold-plated tweezer tips installed. For curved tips, carefully unscrew the existing tips and replace them with the curved ones, ensuring they are securely fastened.
- Kelvin Clips (Plus Option): To use the Kelvin clips, gently pull out the tweezer arm assembly from the main unit. Insert the Kelvin clip connector into the port. Ensure a firm connection.
5.3 Powering On/Off
Press and hold the power button (usually located on the side or top of the device) for a few seconds to turn the LCR-ST2 on or off.
6. Operating Instructions
6.1 Basic Measurement (Auto Recognition)
The LCR-ST2 features automatic recognition of R, C, and L components. Simply connect the component to the tweezer tips or Kelvin clips, and the device will automatically detect the component type and display its primary parameters.
6.2 Selecting Test Frequency
The device supports five test frequencies: 100Hz, 120Hz, 1kHz, 10kHz, and 100kHz. Use the frequency selection button (refer to the device interface) to cycle through these options. Choose the appropriate frequency based on the component type and desired measurement accuracy.
6.3 RMS Test Levels
Adjust the RMS test level (0.1V, 0.3V, 0.6V, 1.0V) to optimize measurements for different components. Lower voltages (0.1V) are suitable for sensitive or low-impedance devices, while higher voltages (1.0V) can provide more accurate readings for stable components.
6.4 Series/Parallel Equivalent Model
The LCR-ST2 can display both series and parallel equivalent values simultaneously. This feature helps in understanding the component's behavior more accurately by accounting for parasitic elements. The device automatically selects the appropriate model (Series for Low Q Value < 10, Parallel for High Q Value > 10).
6.5 Intelligent Sorting & Comparison
This feature allows for rapid testing and sorting of components. You can set nominal values and tolerances, and the device will indicate "PASS" or "NG" (Not Good) based on the component's measured values. This is particularly useful for quality control and batch testing.
6.6 Voltage Measurement
The LCR-ST2 can measure DC voltage up to ±30V. Connect the Kelvin clips or tweezer tips across the points where you want to measure the voltage. The device will automatically switch to voltage measurement mode if a voltage is detected.
6.7 Auto-Rotate Screen
The display automatically rotates based on the device's orientation, allowing for comfortable use by both left-handed and right-handed users.
6.8 Auto Power-Off Settings
To conserve battery, the device can be set to automatically power off after a period of inactivity. You can configure this setting to "Never", "5 minutes", "15 minutes", or "30 minutes" via the system settings menu.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the device. Do not use abrasive cleaners or solvents. Ensure the tweezer tips and Kelvin clips are free from debris for accurate measurements.
- Battery Care: Charge the device regularly, even if not in frequent use, to maintain battery health. Avoid fully discharging the battery for extended periods.
- Storage: Store the LCR-ST2 in its provided storage bag when not in use to protect it from dust, moisture, and physical damage. Store in a cool, dry place within the specified storage temperature range (-20℃ ~ 60℃).
- Tip Replacement: If the gold-plated tweezer tips become worn or damaged, they can be replaced. Refer to section 5.2 for instructions on changing tips.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not turn on. | Low or depleted battery. | Charge the device using the Type-C cable. |
| Inaccurate or unstable readings. | Poor contact with component; dirty tips; incorrect test frequency/level; component damage. | Ensure firm contact. Clean tips. Select appropriate test frequency and RMS level. Check component integrity. Perform calibration if available in settings. |
| "NG" (Not Good) displayed during sorting. | Component value outside set tolerance. | Verify the component's expected value and the set tolerance. The component may indeed be faulty. |
| Display not rotating automatically. | Sensor issue or feature disabled. | Check system settings to ensure auto-rotate is enabled. If issue persists, contact support. |
9. User Tips
(Specific user tips based on reviews and Q&A are not available at this time. General tips for LCR meters include:)
- For very small SMD components, ensure the tweezer tips make solid contact with both ends of the component to get accurate readings.
- When measuring electrolytic capacitors, pay attention to polarity if applicable, although LCR meters typically measure impedance regardless of polarity.
- Utilize the different test frequencies to characterize components more thoroughly, especially for inductors and capacitors where impedance changes with frequency.
- The Kelvin clips are excellent for minimizing lead resistance when measuring low-value resistors or inductors.
10. Warranty and Support
The FNIRSI LCR-ST2 undergoes strict quality inspection before being shipped. For any questions, technical assistance, or support needs, please contact the seller or manufacturer directly. Keep your purchase records for warranty claims.
The product is certified with CE, ensuring compliance with European safety, health, and environmental protection requirements.
