GVDA GD120B Digital Multimeter User Manual

1. Safety Information

WARNING: To avoid possible electric shock or personal injury, please observe the following specifications:

• Read this manual carefully and pay special attention to safety warning information before using the meter.
• Operate the meter according to the manual; otherwise, the protection function provided by the instrument may be damaged or weakened.
• Take special care when measuring values that exceed 60VDC, 30VAC RMS, or 42V. This kind of voltage has the danger of electric shock.
• Do not measure voltage higher than the rated value between terminals or between terminals and ground.
• Measure a known voltage to check whether the meter works normally. If it is not normal or damaged, do not use it again.
• Before using the meter, check whether there are cracks or damaged plastic parts in the instrument shell. If so, do not use it again.
• Before using the meter, check whether the probe is cracked or damaged. If so, replace the probe with the same model and the same electrical specification.
• Use the meter according to the measurement category, voltage, or current rating specified in the meter or manual.
• Observe local and national safety regulations. Wear personal protective equipment (such as approved rubber gloves, masks, and flame retardant clothing, etc.) to prevent injury caused by electric shock and electric arc when dangerous live conductors are exposed.
• When the 'battery' symbol is displayed on the meter, replace the battery in time to prevent measurement error.
• Do not use the meter in an environment with explosive gas or steam or a humid environment.
• When using the probe, hold your fingers behind the probe finger guard.
• When measuring, connect the null or ground wire first, then the live wire; when disconnected, disconnect the live wire first, and then the null or ground wire.
• Remove the probe from the meter before opening the case or battery cover. Do not use the meter when the meter is disassembled or the battery cover is opened.
• The meter can only be used together with the probe provided to meet the requirements of the safety standard. If the probe is damaged and needs to be replaced, the probe of the same model and electrical specification must be replaced.

2. Product Overview

The GVDA GD120B is an intelligent True RMS digital multimeter designed for professional and enthusiast use. It features intelligent identification and manual function modes, a full-color VA display, and an analog bar graph. This multimeter can measure a wide range of electrical parameters including AC/DC voltage, AC/DC current, resistance, capacitance, frequency, diode, continuity, Non-Contact Voltage (NCV), and temperature.

2.1. Key Features

• HD Colour LCD Display
• Maximum 6000 Counts display
• Non-contact AC voltage detection (NCV)
• Sampling Rate: About 3 times per second
• Over range display: "OL"
• Low voltage display: Low battery indication
• Stable performance, high precision, high reliability, clear readings, and overload protection.
• True RMS measurement
• Live wire detecting
• Built-in LED flashlight
• Soft protective cover for durability

2.2. Product Components

• Warning indicator: Visual alert for certain conditions.
• Display: HD Colour LCD for readings and indicators.
• On/off button: Powers the device on or off.
• SMART key: Activates intelligent (AUTO) measurement mode.
• FUNC key / Flashlight key: Toggles functions or activates the flashlight.
• SEL/ key: Selects measurement ranges or turns on/off backlight.
• Data hold button: Freezes the current display reading.
• Range switching: For manual selection of measurement ranges.
• Input jacks: For connecting test probes (Current, COM, and other functions).
• NCV Sensor area: For non-contact voltage detection.
• Flashlight: Integrated LED light for illuminating work areas.

3. Setup

3.1. Battery Installation

The GVDA GD120B Multimeter requires 4 x 1.5V AAA batteries (not included) for operation.

1. Ensure the multimeter is powered off and disconnect any test probes.
2. Locate the battery compartment on the back of the device.
3. Use a screwdriver to open the battery cover.
4. Insert 4 AAA batteries, ensuring correct polarity (+/-).
5. Replace the battery cover and secure it with the screw.

3.2. Probe Connection

Connect the test probes to the appropriate input jacks on the multimeter before performing any measurements.

• Insert the black test probe into the "COM" (Common) jack.
• For most measurements (voltage, resistance, capacitance, frequency, diode, continuity, temperature), insert the red test probe into the "VΩHz" jack.
• For current measurements (AC/DC Current), insert the red test probe into the "A" or "mA" jack, depending on the expected current range. The meter will automatically indicate the correct jack.

4. Operating Instructions

4.1. Power On/Off

• Press and hold the power button () for approximately 2 seconds to turn the multimeter on or off.

4.2. Gear Selection (Measurement Modes)

The GD120B offers both intelligent (AUTO) and manual measurement modes.

• Intelligent (AUTO) Measurement Mode: This is the default mode when powered on. The display will show "Auto". In this mode, the meter automatically identifies and measures DC voltage, AC voltage, resistance, and continuity.
• Manual Mode: Press the "FUNC" key to switch to manual mode. Press the "SEL/" key to cycle through different measurement functions (e.g., AC Voltage, DC Voltage, Resistance, Capacitance, Frequency, Diode, Continuity, Temperature). Press the "SMART" key to return to intelligent (AUTO) measurement mode.

4.3. Data Hold

• Press the "H" button to hold the current reading on the display. Press it again to release the hold function.

4.4. Flashlight

• Press and hold the "FUNC" key for about 2 seconds to turn the LED flashlight on or off.

4.5. Backlight

• Press the "SEL/" key to turn the display backlight on or off. (Note: VA display does not have this function).

4.6. Automatic Current Identification Function

• When a probe is inserted into the "A" jack, the meter will automatically switch to the "A" gear and enter the current measurement function.

4.7. Auto Power Off

• The meter will automatically shut down after approximately 15 minutes of inactivity to save battery energy. The 'auto power off' symbol will be displayed.
• To disable auto power off, press and hold the power button to turn on the meter. The 'auto power off' symbol will not be displayed.

4.8. Specific Measurement Operations

WARNING: Do not measure voltage higher than 600V; otherwise, the meter may be damaged. Pay special attention to safety when measuring high voltage to avoid electric shock or personal injury. Before use, test a known voltage with the meter to confirm that the meter is in good condition.

4.8.1. Smart (AUTO) Measurement

This mode is ideal for general use as the meter automatically detects the type of measurement.

1. Power on the meter. It will default to "Auto" mode.
2. Connect the black probe to "COM" and the red probe to "VΩHz".
3. Contact the probes to the circuit or component to be measured. The meter will automatically identify and display DC voltage, AC voltage, resistance, or continuity.
4. For continuity, if resistance is less than ~50Ω, the buzzer will sound and the indicator light will turn on.

Note: The minimum measurable voltage in Smart (AUTO) mode is 0.8V.

4.8.2. AC/DC Voltage Measurement

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the voltage measurement gear (displaying "V" or "mV").
3. Press "FUNC" again to toggle between AC voltage (displaying "AC") and DC voltage (displaying "DC").
4. Connect the black probe to "COM" and the red probe to "VΩHz".
5. Contact the probes across the measured power supply (in parallel).
6. Read the voltage from the display.

4.8.3. Resistance Measurement

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the resistance measurement gear (displaying "Ω").
3. Connect the black probe to "COM" and the red probe to "VΩHz".
4. Contact the probes across the measured resistance (in parallel).
5. Read the resistance value from the display.

4.8.4. Continuity Test

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the continuity gear (displaying the continuity symbol).
3. Connect the black probe to "COM" and the red probe to "VΩHz".
4. Contact the probes across the circuit or component.
5. If the resistance is less than approximately 50Ω, the buzzer will sound and the indicator light will turn on.

4.8.5. Frequency/Duty Measurement

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the frequency/duty gear (displaying "Hz%").
3. Connect the black probe to "COM" and the red probe to "VΩHz".
4. Contact the probes across the measured power supply.
5. Read the frequency or duty cycle from the display.

4.8.6. Capacitance Measurement

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the capacitance measurement gear (displaying the capacitance symbol).
3. Connect the black probe to "COM" and the red probe to "VΩHz".
4. Contact the probes across the capacitor to be measured.
5. Read the capacitance value from the display.

4.8.7. Diode Test

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the diode test gear (displaying the diode symbol).
3. Connect the black probe to "COM" and the red probe to "VΩHz".
4. Contact the probes across the diode.
5. Read the forward voltage drop from the display.

4.8.8. Temperature Measurement

A K-type temperature probe is included for temperature measurements.

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the temperature measurement gear (displaying "°C/°F").
3. Connect the K-type temperature probe to the "VΩHz" and "COM" jacks.
4. Place the tip of the temperature probe on or near the object whose temperature is to be measured.
5. Read the temperature from the display.

4.8.9. Non-Contact AC Voltage Detection (NCV)

This feature allows detection of AC voltage without direct contact with wires.

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the NCV function (displaying "NCV").
3. Place the NCV sensor area of the multimeter near the AC voltage source (e.g., a live wire or outlet).
4. The meter will indicate the presence of AC voltage through visual and/or audible alerts.

4.8.10. Live Wire Detecting

This function helps identify live wires in an AC circuit.

1. Power on the meter.
2. Press the "FUNC" key to enter manual mode, then press "SEL/" to select the Live function (displaying "Live").
3. Connect the red probe to the "VΩHz" jack.
4. Touch the tip of the red probe to the wire or terminal suspected of being live.
5. The meter will indicate a live wire through visual and/or audible alerts.

5. Maintenance

5.1. Cleaning

• Wipe the meter with a soft, damp cloth. Do not use abrasives or solvents.

5.2. Replacing Battery

When the low battery indicator appears on the display, replace the batteries promptly to ensure accurate measurements.

1. Ensure the multimeter is powered off and all test probes are disconnected.
2. Open the battery compartment cover on the back of the device.
3. Remove the old 4 x 1.5V AAA batteries.
4. Insert new 4 x 1.5V AAA batteries, observing correct polarity.
5. Close the battery compartment cover securely.

5.3. Replacing Fuse

If the fuse is burnt out, the symbol "FUSE" will be displayed when the current gear is selected. Replace the fuse immediately.

1. Ensure the multimeter is powered off and all test probes are disconnected.
2. Open the battery compartment cover. The fuse is typically located near the battery compartment.
3. Carefully remove the old fuse (F600mA/250V fuse).
4. Install a new fuse of the exact same type and rating.
5. Close the battery compartment cover securely.

6. Troubleshooting

• No display or faint display: Check battery level and replace if necessary. Ensure batteries are installed with correct polarity.
• Incorrect readings: Verify that the correct measurement mode is selected and probes are connected to the appropriate jacks. Ensure good contact between probes and the circuit/component.
• "OL" displayed: This indicates an over-range condition. The measured value exceeds the maximum range of the selected function. Switch to a higher range if available, or if in AUTO mode, the value is simply too high for the meter to measure.
• "FUSE" displayed: The fuse for current measurement is blown. Refer to section 5.3 for fuse replacement.
• Meter does not respond in AUTO mode for low voltage: The minimum measurable voltage in Smart (AUTO) mode is 0.8V. For voltages below this, the meter may not register a reading.

7. Specifications

8. User Tips

• Low Voltage in Auto Mode: Be aware that the Smart (AUTO) measurement mode has a minimum measurable voltage of 0.8V. For very low DC or AC voltages (e.g., 0.1-0.7V), the meter may not provide a reading in AUTO mode. Consider using manual mode for precise low-voltage measurements if the meter supports specific low-voltage ranges.
• Automotive Use: This multimeter is suitable for general electrical work, including many automotive applications. Its ability to measure DC voltage, resistance, and continuity makes it useful for diagnosing car electrical systems.
• Smallest Resistance: The smallest resistance range is 600Ω. If you need to measure resistances smaller than this with high precision, ensure the probes are properly calibrated and consider the meter's accuracy specifications for that range.
• Protective Cover: Always use the included soft protective cover to shield the multimeter from drops and impacts, extending its lifespan.

9. Warranty and Support

The GVDA GD120B Digital Multimeter comes with a 24-month manufacturer's limited warranty for defective items (excluding items damaged and/or misused after receipt). Accessories typically come with a 3-month warranty. For warranty claims or technical support, please contact your retailer or the GVDA Official Store directly.

For a comprehensive guide and additional details, you may refer to the official user manual PDF: View User Manual (PDF)