Using a digital multimeter (DMM) is essential for diagnosing electrical issues, measuring voltage, resistance, and current. Here’s a step-by-step guide:

Basic Functions of a Digital Multimeter

1. Measuring Voltage (DC/AC)
   • Set the dial to V (DC voltage) or V~ (AC voltage).
   • Insert the black probe into the COM port and the red probe into the V port.
   • Touch the probes to the circuit terminals (red to positive, black to negative).
   • Read the voltage on the display.
2. Measuring Resistance (Ω)
   • Set the dial to Ω (ohms).
   • Insert the probes into COM and VΩ ports.
   • Touch the probes to both ends of the resistor.
   • Read the resistance value.
3. Measuring Current (A/mA)
   • Set the dial to A or mA (depending on expected current).
   • Insert the black probe into COM and the red probe into A/mA.
   • Connect the probes in series with the circuit.
   • Read the current value.
4. Continuity Testing
   • Set the dial to the continuity mode (usually a diode symbol).
   • Insert probes into COM and VΩ.
   • Touch the probes to both ends of a wire or connection.
   • If the circuit is complete, the multimeter will beep.
5. Diode Testing

• Set the dial to the diode mode.
• Insert probes into COM and VΩ.
• Touch the probes to the diode terminals.
• A working diode will show a voltage drop in one direction.