Mastech M838 Digital Multimeter Quick Start Guide

Brand: Mastech

Model: M838

SKU: M838CBGLO

Safety Precautions

⚠️ General Warning: Special attention is required when using this test and measurement instrument. Improper usage can lead to electric shock and equipment damage.

Use appropriate measurement category (CAT), voltage, and amperage rated probes, test leads, and adapters.
Do not use or store the device in environments with explosive gas, vapor, or under high temperature and humidity.
When handling test probes and crocodile clips, keep fingers behind the physical guard.
Examine test leads before use. Replace any leads with deteriorated insulation.
Connect the common test lead before the live test lead, and remove the live test lead before the common test lead.
Before measuring current, ensure instrument fuses are available and disconnect power to the circuit.
Remove batteries ? if the device is not used for an extended period or stored above 45°C to prevent leakage and damage.

Specifications

Function/Range	Resolution	Accuracy
V~ (AC Voltage) 200V/600V	100mV/1V	±(1.2%+10)
V= (DC Voltage) 200mV/2V/20V/200V	0.1mV/1mV/10mV/100mV	±(0.5%+2)
V= (DC Voltage) 600V	1V	±(0.8%+2)
A= (DC Current) 200μA/2mA/20mA	0.1μA/1μA/0.01mA	±(1.0%+2)
A= (DC Current) 200mA	0.1mA	±(1.5%+2)
A= (DC Current) 10A	10mA	±(3.0%+2)
Ω (Resistance) 200Ω	0.1Ω	±(0.8%+3)
Ω (Resistance) 2kΩ/20kΩ/200kΩ	1Ω/10Ω/100Ω	±(0.8%+2)
Ω (Resistance) 2MΩ	1kΩ	±(1.0%+2)
°C (Temperature) -2°C to -10°C	1°C	±(10%+2)
°C (Temperature) -10°C to 300°C	1°C	±(1.0%+3)
°C (Temperature) 300°C to 1370°C	1°C	±2.0

Usage Guide

Follow these steps for common measurements:

Battery Installation

Open the rear cover of the multimeter. Insert batteries ? as indicated by polarity markings. Close the cover.

DC Voltage Measurement (V=)

Connect the black test lead to the COM terminal.
Connect the red test lead to the VΩmA terminal.
Set the dial to the appropriate DC Voltage range (e.g., 200V or 600V).
Connect the test leads across the DC voltage source. The display will show the voltage reading. Example: 12.3 V.

AC Voltage Measurement (V~)

Connect the black test lead to the COM terminal.
Connect the red test lead to the VΩmA terminal.
Set the dial to the appropriate AC Voltage range (e.g., 200V or 600V).
Connect the test leads across the AC voltage source. The display will show the voltage reading. Example: 230 V.

DC Current Measurement (A=)

Connect the black test lead to the COM terminal.
Connect the red test lead to the 10ADC or mA terminal depending on the expected current.
Set the dial to the appropriate DC Current range (e.g., 200mA or 10A).
Connect the multimeter in series with the circuit to measure current. The display will show the current reading. Example: 2.53 mA.

Continuity and Diode Test

Connect the black test lead to the COM terminal.
Connect the red test lead to the VΩmA terminal.
Set the dial to the continuity/diode symbol (often marked with a diode symbol and/or sound wave).
For continuity, touch the test probes together. The multimeter should beep ?.
For diode test, connect probes to the diode leads. The display will show voltage drop or open circuit.

Resistance Measurement (Ω)

Connect the black test lead to the COM terminal.
Connect the red test lead to the VΩmA terminal.
Set the dial to the appropriate Resistance range (Ω).
Ensure the circuit is de-energized. Connect the test probes across the component to be measured. The display will show the resistance. Example: 156.3 Ω.

hFE Measurement (Transistor Test)

Locate the hFE socket on the multimeter.
Identify the NPN or PNP type of the transistor.
Insert the transistor leads into the corresponding holes in the hFE socket.
The display will show the transistor's current gain (hFE). Example: 100.

Temperature Measurement (°C)

Connect the black test lead of the temperature probe to the COM terminal.
Connect the red test lead of the temperature probe to the VΩmA terminal.
Set the dial to the °C range.
Place the temperature probe tip on the object or in the environment to measure. The display will show the temperature. Example: 27 °C.

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