DMM Operator's Manual

1. Overview

The A830L and A830C multimeters are compact, stable, and anti-dropping devices. They feature a 3 1/2 digit LCD monitor with 15MM high characters for clear readings. The meters utilize large-scale IC A/D converters, overload protection circuits, and offer excellent performance and precise manufacturing, making them handy utility instruments.

The meters can measure DC & AC voltage, DC current, resistance, temperature (only HM-838L), positive diode voltage fall, hFE parameters for transistors, and continuity.

2. Panel Layout

1. LCD Display: 3 1/2 digits, 15MM high characters.
2. Back Light Button Switch: Press to activate the backlight. The light automatically turns off after 5 seconds in dark conditions. It dims when the battery is low.
3. Triode amplifier
4. Rotary Switch: Used to select functions and ranges.
5. VΩmA Input Jack
6. COM Input Jack
7. 10A Input Jack

3. Safety Information

The meters are designed according to IEC-1010 standards for electronic measuring instruments, with an over-voltage category (CAT II) and pollution degree 2.

Always follow all safety and operating instructions to ensure safe usage and maintain the meter in good operating condition.

Safety Symbols:

• ▲: Important safety information; refer to the operating manual.
• ▲: Dangerous voltage may be present.
• ▦: Double insulation (Protection Class II).

4. Special Cautions for Operation

• The meters are safe only when used with the supplied test leads. Replace damaged test leads only with the same model or equivalent electric specifications.
• To avoid electric shock, do not use the meters before the cover is in place.
• Ensure the range switch is set to the correct position for testing.
• To prevent electric shock and instrument damage, input signals must not exceed specified limits.
• When measuring TV sets or switched power supplies, be aware of potential pulses that could damage the circuit.
• Do not change the range switch position randomly during measurement.
• Exercise caution when measuring voltages higher than DC 60V and AC 30V to avoid shock.
• Replace the protection fuse only with the same type and specification.

5. General Specifications

• Max Voltage between input terminal and Earth Ground: CAT II 600V
• Over-range Indication: Displays "1" on the most significant digit.
• Automatic polarity indication: Displays "-".
• Low Battery Indication: Displays "+".
• Max LCD Display: 1999 (3 1/2 digits).
• Fuse Protection: F-200mA/250V (Ø5x20MM).
• Power Supply: 9V battery (6F22 or NEDA 1604).
• Operating Temperature: 0°C to 40°C (relative humidity <85%).
• Storage Temperature: -10°C to 50°C (relative humidity <85%).
• Guaranteed Precision Temperature: 23 ± 5 °C (relative humidity <85%).
• Dimensions: 69x138x31MM (with holster).
• Weight: Approx. 170g (including battery).

6. Testing Specifications

Accuracy is specified for one year after calibration, at 18°C to 28°C (64°F to 82°F) with relative humidity up to 75%.

6-1 DC Voltage

6-2 AC Voltage

6-3 DC Current

6-4 Resistance

6-5 Transistor hFE Test

6-6 Diode Test

6-7 Continuity

6-8 Battery Test

7. Operating Instructions

7-1 Attention before operation

• Check the 9V battery. If the battery voltage is less than 7V, the display will show "△", indicating the battery should be replaced to ensure measuring precision.
• Pay attention to the "▲" symbol next to the input jacks, which signifies that the input voltage or current should be within the specified value.
• The range switch should be set to the desired range before measurement.

7-2 Measuring DC Voltage

• Connect the black test lead to the COM jack and the red lead to the VΩmA jack.
• Set the rotary switch to the desired V== range.
• Connect the test leads across the source or load for measurement.
• The reading will be displayed on the LCD. The polarity of the red lead connection will be indicated along with the voltage value.
• NOTE:
  • If the value to be measured is unknown, set the range selector to the highest position.
  • If "1" or "-1" is displayed, it indicates an over-range situation, and a higher range must be selected.
  • If "▲" is displayed, it means the input voltage exceeds 600V. While the meter may display a higher voltage, it could damage the internal circuitry or cause a shock.
  • Exercise caution against shock when measuring high voltage.

7-3 Measuring AC Voltage

• Connect the black test lead to the COM jack and the red lead to the VΩmA jack.
• Set the rotary switch to the desired V~ range.
• Connect the test leads across the source or load for measurement.
• The reading will be displayed on the LCD.
• NOTE:
  • If the value to be measured is unknown, set the range selector to the highest position.
  • If "1" or "-1" is displayed, it indicates an over-range situation, and a higher range must be selected.
  • If "▲" is displayed, it means the input voltage exceeds 600V. While the meter may display a higher voltage, it could damage the internal circuitry or cause a shock.
  • Exercise caution against shock when measuring high voltage.

7-4 Measuring DC Current

• Connect the black test lead to the COM jack. For currents up to 200mA, connect the red lead to the VΩmA jack. For currents up to 10A, connect the red lead to the 10A jack.
• Set the rotary switch to the desired A== range.
• Connect the test leads in series with the load under measurement.
• The reading will be displayed on the LCD. The polarity of the red lead connection will be indicated along with the current value.
• NOTE:
  • If the value to be measured is unknown, set the range selector to the highest position.
  • If "1" or "-1" is displayed, it indicates an over-range situation, and a higher range must be selected.
  • The mA jack has a maximum current limit of 200mA, and the 10A jack has a limit of 10A. Exceeding these limits will blow the fuse.
  • The 10A range is not fused. To prevent damage from circuit heating, limit measurement time to less than 1 second.

7-5 Measuring Resistance

• Connect the black test lead to the COM jack and the red lead to the VΩmA jack.
• Set the rotary switch to the desired resistance range.
• Connect the test leads across the resistance to be measured.
• The reading will be displayed on the LCD.
• NOTE:
  • If "1" or "-1" is displayed, it indicates an over-range situation, and a higher range must be selected.
  • For resistances above 1MΩ, the meter may take a few seconds to obtain a stable reading.
  • When checking in-circuit resistance, ensure the circuit under test has no power and all capacitors are fully discharged.
  • If the input is open, "1" will be displayed for over-range.
  • If the value scale to be measured is unknown, set the range selector to the highest position.

7-6 Measuring Temperature

• Set the rotary switch to the °C range position.
• The LCD will display the current ambient temperature.
• To measure temperature with a thermocouple, insert the K-Type thermocouple probe (red into VΩmA jack, black into COM jack).
• The reading will be displayed on the LCD.

7-7 Transistor Testing

• Set the rotary switch to the hFE position.
• Determine if the transistor is NPN or PNP and identify the emitter, base, and collector leads. Insert the leads into the appropriate holes of the hFE socket on the front panel.
• Read the approximate hFE value at the testing condition of base current Ib = 10uA and Vce = 3V.

7-8 Diode Testing

• Connect the black test lead to the COM jack and the red lead to the VΩmA jack (red lead is '+').
• Set the rotary switch to the △ range position.
• Connect the red lead to the anode and the black lead to the cathode of the diode under test.
• The reading will be displayed on the LCD.
• NOTE:
  • The meter will show the approximate forward voltage drop of the diode.
  • If the lead connections are reversed, only "1" will be displayed.

7-9 Continuity Testing

• Connect the black test lead to the COM jack and the red lead to the VΩmA jack.
• Set the rotary switch to the △ range position.
• Connect the test leads across two points of the circuit under test.
• If continuity exists (resistance is less than approximately 50 Ω), the built-in buzzer will sound.
• NOTE: If the input is open, "1" will be displayed.

8. Maintenance

• Before removing the battery door or opening the case, ensure the test leads are disconnected from the measurement circuit to avoid electric shock.
• To prevent electric shock, disconnect test leads from measurement circuits before replacing the fuse. Use only specified fuse ratings: F-200mA/250V.
• Replace test leads if they are exposed. Use leads with the same specifications as the original ones.
• Clean the meter using a moist fabric or a small amount of detergent. Do not use chemical solutions.
• Do not use the meter unless the back cover is properly closed and secured with screws. Stop operation immediately and send the meter for maintenance if any abnormality occurs.

9. Accessories

• Test Leads: rated for 1000V, 10A.
• Battery: 9V, 6F22 or NEDA 1604.
• Fuse: F-200mA/250V.
• K type Thermocouple (only A930C).
• Operator's Manual.
• Holster.