Connect the power supply to the circuit you wish to test and turn it on.
Clip the DMM ground (usually black) lead to the circuit or power supply ground.
Set the DMM selector dial to the Voltage (V) range you think you will see. Most DMMs have several AC and DC voltage range settings. The DMM will also have several current range, resistance and diode settings as well.
Connect the probe lead (usually red) into the DMM voltage socket. Some DMMs have separate sockets for current or voltage/resistance.
Probe the test circuit with the DMM red lead by touching the metal tip to the component you wish to check the voltage (relative to ground) on. The DMM display will show your value in volts. If you only have the least (right hand) digit displayed, switch the voltage range (DMM dial) down for more detail.
If the display blinks or shows OL, over-range or something similar, switch the voltage range to a higher setting until yo see a readable value.
Remove the DMM leads from the test circuit. Turn the circuit power supply off.
Read the current going into the circuit using the DMM by switching the selector dial to Current (I), Amps or mA (milliAmps, 1/1,000 Amps). Choose a high current setting. You can step the setting down to get a detailed reading, but having the current setting too low when current is applied will damage many types of DMMs or blow the current protection fuse.
If the DMM has separate sockets for Current and Voltage readings, plug the black lead into the black (or Return or - ) socket and the red lead into the Current ( I ) socket.
Remove the power supply positive lead from the circuit. Attach the DMM red lead to the power supply positive lead. Connect the DMM black lead to the point where the power supply positive lead was connected to the circuit. The DMM is now in series between the power supply and the circuit.
Turn on the power supply. The DMM will read the current going into the circuit.
To read current through any specific component, you must connect the DMM in series with the component in the same way as the DMM was put in series between the power supply and total circuit.
Turn off the power supply. Remove the DMM and reattach the power supply to the circuit.
Switch the DMM to resistance (often shown with the Greek letter Omega) and the 1K scale.
Connect the red DMM lead to one end of the resistor and the black lead to the other. The meter will read around 100. It will give the same reading if you reverse the leads.
Switch the DMM to the diode symbol (an arrow with a line across the tip) if available on your DMM or switch to the 10K-ohm scale.
Connect the black lead to the end of the diode with the black stripe. Connect the red lead to the other end. You should get a small reading on the DMM.
Reverse the leads and the meter will give an open reading, since the diode is back-biased.