ANENG DT-838 Digital Multimeter User Manual

1. Introduction

This manual provides detailed instructions for the safe and effective operation of your ANENG DT-838 Digital Multimeter. The DT-838 is a compact, battery-powered, 3 1/2 digit multimeter designed for measuring DC/AC voltage, DC current, resistance, temperature, diode, and transistor hFE. Please read this manual thoroughly before use and retain it for future reference.

2. Safety Information

WARNING: To avoid electrical shock or damage to the meter, observe the following safety rules:

• Always ensure the test leads are properly connected and the function switch is set to the correct range before making any measurements.
• Do not apply more than the rated voltage, as marked on the meter, between the terminals or between any terminal and earth ground.
• Use extreme caution when working with voltages above 60V DC or 30V AC RMS. Such voltages pose a shock hazard.
• Disconnect the circuit power and discharge all high-voltage capacitors before testing resistance, continuity, diodes, or hFE.
• Always replace the battery and fuse with the specified type and rating.
• Do not operate the meter if it appears damaged or if the case is open.
• Remove test leads from the meter before opening the battery cover.

The back of the device also contains a warning regarding electrical shock and the need to remove inputs before opening the casing.

Image: Rear view of the DT-838 multimeter, displaying safety warnings and specifications for power supply (9V battery) and fuse.

3. Product Overview

The ANENG DT-838 is a portable digital multimeter featuring a clear LCD display and a rotary switch for function and range selection.

Image: Front view of the ANENG DT-838 Digital Multimeter, showing the LCD screen, rotary function switch, and input jacks.

3.1 Components

• LCD Display: 3 1/2 digits, 7-segment, 0.5" high, displays measurement readings.
• Rotary Function Switch: Used to select the desired measurement function (Voltage, Current, Resistance, Temperature, hFE, Diode) and range.
• Input Jacks:
  • "VΩmA" Jack: Input for voltage, resistance, and current (up to 200mA) measurements.
  • "10A" Jack: Input for high current (up to 10A) measurements.
  • "COM" Jack: Common (negative) input for all measurements.
• hFE Socket: For testing NPN/PNP transistors.
• Temperature Input: For connecting the temperature probe.

4. Specifications

The ANENG DT-838 Digital Multimeter offers the following technical specifications:

• Max Display: 1999 (3 1/2 digits)
• Sampling Rate: 2-3 times per second
• Overload Protection: On all ranges
• Power Supply: 9V Battery (NEDA 1604 or 6F22 type)
• Dimensions: Approx. 120 x 66 x 20mm (L x W x H)
• Color: Black

5. Setup and Battery Installation

The ANENG DT-838 requires a 9V battery for operation. The battery is typically not included.

5.1 Battery Installation

1. Ensure the multimeter is turned OFF and disconnect all test leads from the input jacks.
2. Locate the battery compartment cover on the back of the meter.
3. Carefully slide or unscrew the cover to open the compartment.
4. Connect a 9V battery (NEDA 1604 or 6F22 type) to the battery clips, observing correct polarity.
5. Place the battery into the compartment and replace the cover, ensuring it is securely closed.

Image: The DT-838 multimeter with test leads connected to a 9V battery, demonstrating a basic setup for power testing.

6. Operating Instructions

Before making any measurements, ensure the battery is installed and the test leads are in good condition. Always start with the highest range setting for an unknown value and decrease it until a stable reading is obtained.

6.1 Measuring DC Voltage (V=)

1. Insert the red test lead into the "VΩmA" jack and the black test lead into the "COM" jack.
2. Set the rotary switch to the desired DC Voltage (V=) range (e.g., 20V, 200V, 1000V).
3. Connect the test leads across the component or circuit to be measured, observing polarity.
4. Read the voltage value on the LCD display.

6.2 Measuring AC Voltage (V~)

1. Insert the red test lead into the "VΩmA" jack and the black test lead into the "COM" jack.
2. Set the rotary switch to the desired AC Voltage (V~) range (e.g., 200V, 750V).
3. Connect the test leads across the component or circuit to be measured. Polarity is not critical for AC measurements.
4. Read the voltage value on the LCD display.

6.3 Measuring DC Current (A=)

CAUTION: Never connect the meter in parallel with a voltage source when measuring current. This can blow the fuse or damage the meter.

1. For currents up to 200mA: Insert the red test lead into the "VΩmA" jack and the black test lead into the "COM" jack.
2. For currents up to 10A: Insert the red test lead into the "10A" jack and the black test lead into the "COM" jack.
3. Set the rotary switch to the appropriate DC Current (A=) range (e.g., 2000uA, 20mA, 200mA, 10A).
4. Open the circuit where current is to be measured and connect the meter in series with the load.
5. Read the current value on the LCD display.

6.4 Measuring Resistance (Ω)

WARNING: Ensure the circuit is de-energized and all capacitors are discharged before measuring resistance.

1. Insert the red test lead into the "VΩmA" jack and the black test lead into the "COM" jack.
2. Set the rotary switch to the desired Resistance (Ω) range (e.g., 200Ω, 2000Ω, 20KΩ, 200KΩ, 2000KΩ).
3. Connect the test leads across the component to be measured.
4. Read the resistance value on the LCD display.

6.5 Measuring Temperature (°C)

1. Ensure the multimeter is turned OFF.
2. Insert the temperature probe into the designated temperature input jacks (usually marked with a thermometer symbol). Observe polarity if applicable.
3. Set the rotary switch to the "TEMP °C" position.
4. Place the tip of the temperature probe on or near the object whose temperature is to be measured.
5. Read the temperature value on the LCD display.

Image: The DT-838 multimeter connected to a temperature probe, demonstrating its capability to measure temperature.

6.6 Diode Test (→|)

WARNING: Ensure the circuit is de-energized and all capacitors are discharged before testing diodes.

1. Insert the red test lead into the "VΩmA" jack and the black test lead into the "COM" jack.
2. Set the rotary switch to the Diode (→|) position.
3. Connect the red lead to the anode and the black lead to the cathode of the diode. A forward voltage drop (typically 0.5V to 0.8V for silicon diodes) will be displayed.
4. Reverse the leads. An open circuit ("OL" or "1") should be displayed for a good diode.

6.7 Transistor hFE Test

1. Set the rotary switch to the "hFE" position.
2. Identify if the transistor is NPN or PNP.
3. Insert the transistor's emitter, base, and collector leads into the corresponding holes in the hFE socket.
4. Read the hFE (DC current gain) value on the LCD display.

7. Maintenance

Proper maintenance ensures the longevity and accuracy of your multimeter.

7.1 Battery Replacement

When the battery voltage drops below the operating voltage, the "BAT" symbol will appear on the LCD display. Replace the battery as described in Section 5.1.

7.2 Fuse Replacement

WARNING: To avoid fire or electrical shock, replace the fuse only with the specified type and rating.

The DT-838 typically uses a 500mA/250V fast-blow fuse for the "VΩmA" input and a 10A/250V fast-blow fuse for the "10A" input. Refer to the back of the meter for exact fuse specifications.

1. Ensure the multimeter is turned OFF and disconnect all test leads.
2. Open the back case of the meter (this may require unscrewing).
3. Carefully remove the old fuse and replace it with a new one of the identical type and rating.
4. Close the case securely.

7.3 Cleaning

Wipe the meter with a damp cloth and a mild detergent. Do not use abrasives or solvents.

8. Troubleshooting

9. Warranty and Support

This product is designed for reliability and performance. For specific warranty information or technical support, please refer to the documentation provided at the time of purchase or contact your retailer. Keep your purchase receipt as proof of purchase.