GVDA GD120B / GD118B Smart Digital Multimeter User Manual

1. Safety Information

1.1. Safety Statement

Caution: Indicates an operation that may cause damage to the meter or equipment.

Warning: Indicates an operation that may cause danger to users.

1.2. Safety Instructions

The meter conforms to IEC61010-1 CAT.III 600V overvoltage safety standard and pollution level 2.

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 carries 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 for 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 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) to prevent injury caused by electric shock and electric arc when dangerous live conductors are exposed.
• When the "" symbol is displayed on the meter, replace the battery in time to prevent measurement error.
• Do not use the meter in environments with explosive gas, steam, or high humidity.
• 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 disconnecting, 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 it is disassembled or the battery cover is open.
• The meter can only be used with the provided probes to meet safety standards. If a probe is damaged and needs replacement, use a probe of the same model and electrical specification.

2. Product Overview

This meter is an intelligent true RMS digital multimeter. It features intelligent and professional measurement functions, full functionality, gear display, and an analog bar multiple display.

2.1. Components and Display

1. Alarm indicator
2. Display
3. Function key
4. Current input jack
5. COM input jack
6. Input jack for other functions (except current)
7. NCV Sensor area
8. Flashlight

2.2. Package Contents

The package typically includes:

• Smart Digital Multimeter (GD120B or GD118B)
• Test Leads (Original pen)
• Thermocouple Probe
• User Manual
• Storage Bag
• Gift Box

3. Setup

3.1. Battery Installation

The multimeter requires 4 AAA batteries (not included) for operation.

1. Turn off the meter power and remove the probes.
2. Remove the screw fixing the battery cover and then remove the battery cover.
3. Insert 4 AAA batteries, paying attention to the correct polarity.
4. Install the battery cover back to its original position and secure it with screws.

Warning:

• To avoid electric shock or personal injury caused by wrong readings, replace the battery immediately when the battery is low.
• Do not discharge the battery by shorting it or reversing its polarity.
• To operate and maintain the meter safely, remove the batteries when not used for a long time to prevent battery leakage from damaging the product.

4. Operating Instructions

4.1. Power On / Off

Press and hold the "" (Power) key for about 2 seconds to turn the meter on or off.

4.2. Gear Selection

Press the "FUNC" key to switch to manual mode. Press "FUNC" again to select the desired measurement gear (left or right). Press the "SMART" key to return to the intelligent (AUTO) measurement mode. The meter defaults to intelligent measurement mode upon power-on.

4.3. Data Hold

Press the "H / " key to turn data holding on or off.

4.4. Flashlight and Backlight

• Flashlight: Press and hold the "SEL / " key for about 2 seconds to turn the flashlight on or off.
• Backlight: Press the "H / " key to turn the backlight on or off. Note: VA display does not have this function.

4.5. Automatic Current Identification Function

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

4.6. Auto Power Off

After power on, auto power off is enabled by default, and the "" symbol will be displayed. Without any key operation for about 15 minutes, the meter will automatically shut down to save battery energy. Press and hold the "SEL / " key to cancel the auto power off function.

4.7. Measurement Operation Warnings

• 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 it is in good condition.

4.8. Smart (AUTO) Measurement

This is the default measurement mode when powered on. In this mode, DC voltage, AC voltage, resistance, and continuity can be measured, and the meter automatically identifies the measurement signal.

1. Press the Power key to turn on; "Auto" will display, and the meter enters intelligent measurement mode.
2. Insert the red probe into the "" jack and the black probe into the "COM" jack.
3. Contact the probes with both ends of the measured power supply or resistance (parallel). The meter will automatically recognize the measured signal.
4. When measuring resistance, if the value is less than about 50 Ω, the buzzer sounds, and the indicator light is on.
5. Read the results from the display.

NOTE: The minimum measurable voltage in this mode is 0.8V.

4.9. Professional Measurement Modes

4.9.1. AC/DC Voltage Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "" gear.
3. Press the "SEL / " key to select AC voltage (displaying "AC") or DC voltage (displaying "DC").
4. Insert the red probe into the "" jack and the black probe into the "COM" jack.
5. Contact the probes with both ends of the measured power supply (parallel).
6. Read the results from the display.

4.9.2. Resistance Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "Ω" gear.
3. Insert the red probe into the "" jack and the black probe into the "COM" jack.
4. Contact the probes with both ends of the measured resistance (parallel).
5. Read the results from the display.

4.9.3. Continuity Test

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "" gear.
3. Insert the red probe into the "" jack and the black probe into the "COM" jack.
4. Contact the probes with both ends of the circuit or resistance (parallel).
5. If the resistance value is less than about 50 Ω, the buzzer sounds, and the indicator light is on.
6. Read the results from the display.

4.9.4. Frequency/Duty Cycle Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "Hz%" gear.
3. Insert the red probe into the "" jack and the black probe into the "COM" jack.
4. Contact the probes with both ends of the measured power supply.
5. Read the results from the display.

4.9.5. Capacitance Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "" gear.
3. Insert the red probe into the "" jack and the black probe into the "COM" jack.
4. Contact the probes with both ends of the measured capacitance (parallel).
5. Read the results from the display.

4.9.6. Diode Test

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "" gear.
3. Insert the red probe into the "" jack and the black probe into the "COM" jack.
4. The red probe contacts the anode of the diode, and the black probe contacts the cathode of the diode.
5. If the probe polarity is opposite to the diode polarity, the display will show "OL".
6. Read the results from the display.

4.9.7. Temperature Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "°C/°F" gear.
3. Insert the positive pole of the K-type thermocouple into the "" jack and the negative pole into the "COM" jack.
4. The thermocouple probe contacts the measured object.
5. Read the results from the display.

4.9.8. Non-Contact AC Voltage Detection (NCV)

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "NCV" gear. The "NCV" symbol will be displayed.
3. Gradually move the NCV sensor area close to the conductor.
4. When a weak electric field signal is detected, it will display "---L"; the buzzer will sound slowly, and the green light will turn on.
5. When a strong electric field signal is detected, it will display "---H"; the buzzer will sound quickly, and the red light will turn on.

4.9.9. Live Wire Detecting

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "NCV" gear.
3. Press the "SEL / " key to display the "LIVE" symbol.
4. Insert the red probe into the "" jack and remove the black probe.
5. Use the red probe to contact the conductor.
6. When a weak electric field signal is detected, it will display "---L"; the buzzer will sound slowly, and the green light will turn on.
7. When a strong electric field signal is detected, it will display "---H"; the buzzer will sound quickly, and the red light will turn on.

4.9.10. AC/DC Current Measurement

1. Press the Power key to turn on; "Auto" will display.
2. Press the "FUNC" key to select the "" gear. Alternatively, insert the red probe into the "A" jack to automatically select the "" gear.
3. Press the "SEL / " key to select DC current (displaying "DC") or AC current (displaying "AC").
4. Insert the red probe into the "A" jack and the black probe into the "COM" jack.
5. Disconnect the measured power supply, connect the meter in series with the power supply, and then turn on the measured power supply.
6. Read the results from the display.

Caution: Do not measure current greater than 10A, otherwise the fuse will be burnt out.

5. Maintenance

5.1. Cleaning

When cleaning the meter, please follow these steps:

1. Turn off the meter power and remove the probes.
2. Wipe the case with a damp cloth or mild detergent. Do not use abrasives or solvents.
3. Wipe the contacts in each input socket with a clean swab soaked in alcohol.

Warning: Always keep the inside of the meter clean and dry to prevent electric shock or damage to the meter.

5.2. Battery Replacement

Refer to Section 3.1 for detailed battery replacement instructions.

5.3. Fuse Replacement

If the fuse is burnt out, the symbol "" will be displayed. When the current gear is selected, "FUSE" will be displayed. It is not allowed to measure current until the fuse is replaced.

1. Turn off the meter power and remove the probes.
2. Remove the screw fixing the back cover and remove the back cover.
3. Remove the burnt-out fuse, replace it with a new one of the same specification (F10A/250V fuse), and ensure that the fuse is installed in the safety clip and clamped tightly.
4. Install the back cover and fix it with screws.

Warning: After opening the back cover of the meter, do not use the instrument for measurement to prevent electric shock or damage to the instrument.

6. Troubleshooting

Problem	Indication	Solution
Low Battery	"" symbol displayed	Replace with new AAA batteries (refer to Section 5.2).
Blown Fuse	"" symbol or "FUSE" displayed	Replace the fuse (F10A/250V) (refer to Section 5.3).
Over Range	"OL" displayed	The measured value exceeds the meter's range. Select a higher range or ensure the input is within limits.
Meter does not power on	No display	Check battery installation and charge level. Ensure power button is pressed for 2 seconds.

7. Specifications

7.1. General Technical Specifications

• Safety Standard: CAT. III 600V
• Pollution Level: 2
• Altitude: < 2000m
• Operating Temperature: 0 ~ 40 °C (<80% RH, <10°C non-condensing)
• Storage Temperature: -10 ~ 60 °C (<70% RH, remove the battery)
• Temperature Coefficient: 0.1 x accuracy / °C (<18°C or >28°C)
• Max. Voltage between terminals and earth ground: DC/AC 600V
• Fuse Protection: F10A/250V fuse
• Sampling Rate: Approx. 3 times/second
• Display: 6000 counts, HD Colour Display
• Over Range Indication: "OL"
• Low Battery Indication: "" will be displayed
• Input Polarity Indication: Display "-"
• Power Supply: 4pcs AAA Batteries (not included)
• Dimensions: 146 x 72 x 26mm

7.2. Accuracy Specifications

Accuracy applies within one year after calibration. Reference condition: environment temperature 18°C to 28°C, relative humidity no more than 80%.

7.2.1. DC Voltage

7.2.2. AC Voltage

Impedance: Approx. 10MΩ
Frequency Response: 40Hz~1kHz; TRMS

7.2.3. Resistance

Overload protection: 250V

7.2.4. AC/DC Current

Overload protection: F10A/250V fuse
Frequency Response: 40Hz~1kHz; TRMS

7.2.5. Capacitance

Overload protection: 250V

7.2.6. Frequency/Duty Cycle

Overload protection: 250V

7.2.7. Diode / Continuity

7.2.8. Temperature

Resolution: 1°C/1°F
Note: Use K-type thermocouple probe

8. User Tips

• Always start with the Smart (AUTO) mode for general measurements, as it simplifies the process by automatically detecting the signal type.
• For precise or specific measurements, switch to the appropriate professional mode using the FUNC button.
• When measuring current, always connect the multimeter in series with the circuit and ensure the power is off before connecting to avoid damaging the meter or circuit.
• Utilize the flashlight feature in dimly lit environments for better visibility of test points.
• Regularly check the battery level indicator and replace batteries promptly to ensure accurate readings.

9. Warranty and Support

This GVDA Digital Multimeter is designed for reliability and performance. For any technical support or warranty inquiries, please refer to the official GVDA website or contact your local distributor.

For additional documentation, including the original PDF user manual, please refer to the following resource: User manual (PDF)

Please retain your purchase receipt as proof of purchase for warranty claims.