LCR-T7 Multi-function Tester
User Manual
Features
- 160x128 TFT Display
- Transistor test area
- Zener Diode test area
- IR receiver window
- Multi-function key
- Micro USB Charging Interface
- Charge indicator LED
- Automatic detection of NPN and PNP bipolar transistors, N-channel and P-channel MOSFETS, JFETs, diodes (including double Diodes), N. and P-IGBTS, resistors, Inductors, capacitors, thyristors, triac and battery (0.1-4.5V)
- Automatic detection of Zener diode (0.01-20V)
- Self-test with automatic calibration
- IR decoder (supports Hitachi IR coding)
- IR waveform display
- Auto Power Off (Timeout Settable)
- Built-in rechargeable Li-ion Battery
- Li-ion Battery voltage detection
Performance Parameters
| Component Type | Range | Parameter Description |
|---|---|---|
| BJT | diode forward voltage <4.50V | hFE(DC Current Gain), Ube(Base-Emitter Voltage), Ic (Collector Current), Iceo(Collector Cut-off Current(IB=0)), Ices (Collector short Current), Uf(Forward Voltage of protecting diode) |
| double diode | 0.01-4.50V | Forward voltage drop, junction capacitance, reverse leakage current |
| Zener diode | 0.01-20V | Forward voltage drop, reverse breakdown voltage |
| MOSFET | Cg(Gate Capacitance), Id(Drain Current) at Vgs(Gate to Source Threshold Voltage), Uf(Forward Voltage of protecting diode) | |
| JFET | Drain current Id under Vgs, protection diode forward voltage drop Uf | |
| IGBT | Gate turn-on voltage, gate capacitance Cg, drain resistance Rds, protection diode forward voltage drop Uf | |
| Capacitor | 25pF-100mF | Capacitance Value, Equivalent Series Resistance ESR, Vloss |
| Resistor | 0.01-50MΩ | Resistance |
| Inductor | 0.01mH-20H | Inductance, DC Resistance |
| Thyristor | Gate trigger current <6mA | Forward voltage drop |
| Triac | Forward voltage drop | |
| Battery | 0.1-4.5V | Voltage value, battery polarity |
Testing Procedures
Component Testing
Attention: Capacitors must be discharged before testing. Do not test capacitors in the KAA test area. If a capacitor is accidentally placed in the KAA area, discharge it before moving it to the transistor test area to avoid damaging the instrument.
Place the component into the appropriate test area (Transistor test area for most components, Zener diode test area for Zener diodes). Press the test key. The screen will automatically display the measured component parameters and pin assignments.
For more accurate testing, directly insert components into the test area. For components that cannot be directly inserted, use the test leads. Ensure only two leads are used for testing, and do not leave the third lead unconnected, as it can affect test results.
Warning: Do not use the tester to test components on energized circuit boards, as this can damage the instrument.
Detecting Transistors
In the power-off state or after a test is completed, place the component into the transistor test area, press the locking handle, and short-press the multifunction key. The tester will automatically measure and graphically display the results.
Warning: Always discharge capacitors before connecting them to the tester. The tester may be damaged before it is switched on.
Warning: Do not use the tester to measure batteries with voltages above 4.5V, as this may damage the tester.
Detecting Zener Diodes
When the device is turned off or the test is completed, place the Zener diode into the Zener diode test area, press the locking handle, and briefly press the multifunction button.
Note: Do not place components in the Transistor test area when testing Zener diodes, as this will prevent accurate measurement.
IR Decoder
After component testing is complete, point an infrared remote control at the "IR" test hole of the tester and press a button. If decoding is successful, the tester will display the user code and data code, along with the corresponding infrared waveform. If decoding fails, the user code and data code will not be displayed.
Note: This decoder only supports infrared encoding in the Hitachi format. Other formats are not supported.
Automatic Calibration
Short-circuit the three test sockets and briefly press the multifunction button. The tester will automatically calibrate. Follow the on-screen prompts to disconnect the short wire when required.
Automatic Shutdown
The tester will automatically shut down after a set timeout period (default 30 seconds) when no operation is performed after component testing or IR decoding. Standby power consumption is 0 μA after shutdown.
Battery Management
Battery Voltage Measurement
The built-in lithium battery voltage is detected and displayed before each component measurement. If the battery voltage drops below 3.1V, the tester will shut down automatically. Please charge the battery in this case.
Battery Charging
The charging interface is a standard Micro USB. Use an external 5V power supply or USB power supply for charging.
Note: The charging indicator is red while charging and turns green when charging is complete.
FAQ and Known Issues
Troubleshooting
- Cannot power on: Lithium battery is low. Please charge until the light turns green.
- Inaccurate measurements: Please re-calibrate.
Known Errors and Unsolved Problems
- The current amplification factor of germanium transistors may be measured too high due to high residual current, resulting in a very low base-emitter voltage.
- Capacity values in the reverse direction for Power Schottky Diodes (e.g., MBR3045PT) may not be measurable if only one diode is connected, due to excessive residual current. Cooling the device might help.
- The diode function of a triac gate cannot be examined.
- Source and Drain pins on JFETs may not be detected correctly due to their symmetrical structure. Swapping Source and Drain pins may result in the same display output.
- The tester's output current is 6mA/voltage <5V. High-power IGBTs, thyristors, and Darlington tubes requiring higher current/voltage drive may not be measured accurately. Air core coils and power inductors cannot have their inductance directly measured; series connection is recommended. For capacitors below 20pF, testing a 20pF capacitor is recommended.