ANENG DM850 Digital Multimeter

1. Introduction

The ANENG DM850 series instruments are compact, pocket-sized 3½ digit digital multimeters designed for a wide range of electrical measurements. They are ideal for use in various fields, including laboratories, workshops, for DIY enthusiasts, and general home applications.

This multimeter is capable of measuring DC and AC Voltage, DC Current, Resistance, and Diode. Some models also feature Temperature and Transistor (hFE) measurement functions, as well as an audible continuity test. Full-range overload protection and low battery voltage indication are standard features.

Figure 1: Front view of the ANENG DM850 Digital Multimeter, highlighting its core functions.

2. Safety Warnings

WARNING: READ AND UNDERSTAND THIS MANUAL BEFORE USING THE INSTRUMENT.

Failure to understand and comply with the WARNINGS and operating instructions can result in serious or fatal injuries and/or property damage.

• To avoid electrical shock hazard and/or damage to the instrument, do not measure voltages that might exceed 500V above earth ground.
• Before using the instrument, inspect test leads, connectors, and probes for cracks, breaks, or crazes in the insulation.

3. Setup

3.1. Battery Installation

The multimeter requires a 9V battery (NEDA 1604 6F22 type) for operation. To install the battery:

1. Use a screwdriver to unscrew the screw on the back cover of the multimeter.
2. Remove the battery compartment cover.
3. Connect the 9V battery, ensuring correct positive and negative pole alignment.
4. Place the battery into the compartment and replace the cover.
5. Secure the cover by screwing it back in.

Figure 2: Correct battery installation for the multimeter.

3.2. Adjustable Support Frame

The multimeter features an extendable support frame on the back, allowing it to be angled at 45 degrees for easier viewing and operation.

Figure 3: The multimeter's adjustable support frame for convenient use.

4. Operating Instructions

4.1. Front Panel Description

Figure 4: Detailed view of the multimeter's front panel and internal components.

1. Function and Range Switch: This rotary switch is used to select the desired measurement function (e.g., Voltage, Current, Resistance) and the appropriate range. Always turn the switch to the "OFF" position when the instrument is not in use to conserve battery life.
2. Display: A 3½ digit, 7-segment, 0.5" high LCD for displaying measurement readings.
3. "COM" Jack: This is the common (negative) input terminal. The black test lead should always be connected here.
4. "VΩmA" Jack: This is the positive input terminal for voltage, resistance, and current measurements (except for 10A DC current). The red test lead should be connected here for these functions.
5. "10A" Jack: This is the positive input terminal specifically for 10A DC current measurements. The red test lead should be connected here for this function.
6. HOLD Button: Press this button to freeze the current reading on the display for easy recording. Press again to release.

4.2. AC Voltage Measurement

1. Connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. Set the Function and Range switch to the desired AC Voltage (V~) position. If the voltage is unknown, start with the highest range and reduce it until a stable reading is obtained.
3. Connect the test leads across the device or circuit being measured.
4. The AC voltage value will appear on the digital display.

Figure 5: Measuring common household AC voltage.

4.3. DC Voltage Measurement

1. Connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. Set the Function and Range switch to the desired DC Voltage (V-) position. If the voltage is unknown, start with the highest range and reduce it until a stable reading is obtained.
3. Connect the test leads across the device or circuit being measured.
4. The DC voltage value will appear on the digital display, along with the voltage polarity.

Figure 6: Measuring DC voltage, such as from a 9V battery.

4.4. DC Current Measurement

WARNING: Never connect the multimeter in parallel with a voltage source when measuring current. Always connect in series. Direct contact will burn out the instrument!

1. For measurements between 200µA and 200mA, connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. For 10A measurements, connect the red test lead to the "10A" jack and the black test lead to the "COM" jack.
3. Set the Function and Range switch to the desired DC Current (A-) position.
4. Open the circuit to be measured and connect the test leads IN SERIES with the load.
5. Read the current value on the digital display.

Figure 7: Correct method for measuring current in series. This drawing is for reference only.

Figure 8: Critical warning: Do NOT measure current by direct contact like voltage. This will damage the instrument.

4.5. Resistance Measurement

1. Connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. Set the Function and Range switch to the desired OHM (Ω) position.
3. If the resistance being measured is connected to a circuit, turn off power and discharge all capacitors before measurement.
4. Connect the test leads across the component being measured.
5. Read the resistance value on the digital display.

Figure 9: Accurately measuring resistance with test leads.

4.6. Diode Measurement

1. Connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. Set the Function and Range switch to the Diode (→|) position.
3. Connect the red test lead to the anode of the diode and the black test lead to the cathode.
4. The forward voltage drop in mV will be displayed. If the diode is reversed, "1" will be shown.

Figure 10: Using positive and negative test leads to measure a diode.

4.7. Transistor hFE Measurement

1. Set the Function and Range switch to the hFE position.
2. Determine whether the transistor is PNP or NPN type and locate the Emitter, Base, and Collector leads.
3. Insert the leads into the proper holes of the hFE Socket on the front panel.
4. The meter will display the approximate hFE value at the condition of base current 10µA and VCE2.8V.

Figure 11: Setting the function range switch to hFE to measure transistor type.

4.8. Audible Continuity Test

1. Connect the red test lead to the "VΩmA" jack and the black test lead to the "COM" jack.
2. Set the Function and Range switch to the Continuity (•))) position.
3. Connect the test leads to two points of the circuit to be tested.
4. If the resistance is lower than 30Ω ± 20Ω, the buzzer will sound, indicating continuity.

Figure 12: The buzzer alarm LED lights when test leads are crossed, indicating normal core.

4.9. Temperature Measurement (if applicable)

1. Connect the K-type thermoelectric couple to the "VΩmA" and "COM" jacks.
2. Set the Function and Range switch to the TEMP position.
3. The display will show the temperature value in °C.

4.10. Test Signal Use (if applicable)

1. Set the Function and Range switch to the Test Signal (Hz) position.
2. A test signal (50Hz) will appear between the "VΩmA" and "COM" jacks. The output voltage is approximately 5V p-p with 50kΩ impedance.

4.11. Product Demonstration Video

5. Maintenance

5.1. Battery and Fuse Replacement

The fuse rarely needs replacement and typically blows due to operator error. If the low battery symbol (a battery icon) appears on the display, it indicates that the battery should be replaced.

To replace the battery or the fuse (500mA/250V):

1. Ensure the multimeter is turned OFF and disconnect all test leads from any circuits.
2. Remove the 2 screws located at the bottom of the case.
3. Carefully open the case.
4. Remove the old battery and replace it with a new 9V battery (NEDA 1604 6F22 type), observing correct polarity.
5. If replacing the fuse, carefully remove the old fuse and insert a new one of the correct rating (500mA/250V).
6. Close the case and secure it with the screws.

CAUTION: Before attempting to open the case of the instrument, be sure to disconnect test leads from any energized circuits to avoid shock hazard.

6. Troubleshooting

This section addresses common issues you might encounter with your ANENG DM850 Multimeter.

• Low Battery Indication: If the low battery symbol appears on the display, replace the 9V battery as described in the Maintenance section.
• Product Not Operating Properly: If the product is not operating normally, please provide a detailed video of the product not operating to ANENG customer service. Their experts and technicians can help diagnose the problem and provide a solution.
• Questions About Product Use: This brand product is a technical product and requires a certain degree of electrical knowledge. If you encounter operational problems or do not understand how to use the product, contact ANENG customer service for assistance.
• About Quality Issues: In case of quality problems other than "man-made damage" during the use of the product, replacement services or refunds can be provided. For specific product damage, contact ANENG customer service to confirm and discuss solutions.
• Artificial Damage: This brand is mostly used to detect electrical and other measurement products. It requires a certain degree of electrical knowledge. Pay attention to the use of certain operating procedures, select the correct measurement method, and avoid dangerous events. If the customer uses the product improperly and the use method is not equal, resulting in damage to the product, it will be judged as man-made damage, which is not within the scope of after-sales service of the product.

7. Specifications

Accuracies are guaranteed for 1 year, at 23°C ± 5°C, less than 80% RH.

Figure 13: Physical dimensions and key product parameters.

8. User Tips

• Portability: The compact size of the DM850 makes it easy to carry, offering convenience for on-the-go measurements.
• Current Measurement Safety: Always connect the multimeter in series when measuring current. Never connect it directly across a voltage source, as this can damage the instrument.
• Data Hold: Utilize the 'HOLD' button to temporarily freeze readings on the screen, which is useful for recording measurements in hard-to-reach areas or when the display is not immediately visible.

9. Warranty and Support

9.1. After-Sales Questions

If you have any problems during the use of the product, please contact ANENG customer service. Our customer service team will provide you with satisfactory solutions in a timely manner.

Figure 14: Information regarding ANENG's professional after-sales support.

9.2. Additional Resources

For a comprehensive guide and additional documentation, you may refer to the official user manual PDF. Please contact customer support for the direct link to the PDF manual.