How to Use a Digital Multimeter 20M/10A

By Ryan Long

Multimeters come in two varieties, analog and digital. Multimeters are used to check three main areas in a circuit: voltage, current and resistance. All meters will show results for both alternating current (AC) or direct current (DC) circuits. Digital multimeters will often have a digital readout panel that's easier to understand and a dial on the front to switch between measurement modes. Also on the front panel will be two received sockets to which you will attach your positive and negative tester leads. It is important to learn how to use a digital multimeter if you plan to do any home electrical work.

Digital multimeters have phased out the older analog models.


Step 1

Set your digital multimeter to the appropriate current type (AC or DC) and set the voltage to just higher than the voltage you expect the multimeter to read. You must know if the circuit is AC or DC, and you should have a good idea of what the voltage on the circuit should be before testing voltage.

Step 2

Plug your leads into the appropriate received sockets on the face of the multimeter. Be sure that no part of your body or your clothing is touching the live circuit, nor any nearby tools. Apply the leads to the circuit for DC voltage. The black lead is your ground, and you will touch the red lead to the positive polarity point. Apply the leads to the circuit when testing AC voltage. Adjust the position of the leads until the multimeter displays a steady reading on the LCD. If the multimeter is showing no voltage, make sure that the circuit you are testing is live.

Step 3

Check your reading by applying the leads to more than one area to make sure that you are getting the same reading on the same circuit.


Step 4

Set your digital multimeter for either AC or DC current, then set the dial for the appropriate function. Set your multimeter to the voltage function appropriate for AC or DC, then set sensitivity to the millivolt.

Step 5

Plug the leads into the clamp adapter. Close the head of the clamp adapter around a single wire in the circuit and record your reading.

Step 6

Set your multimeter appropriately to AC or DC if you plan to use your test leads. Apply the leads to a single wire in the circuit and take a reading.


Step 7

Set your multimeter to the continuity function. A lack of power from one end of a circuit to another may be due to a lack of continuity in the circuit.

Step 8

Check that the power in the circuit is off. Make contact with the circuit using your test leads. Most multimeters will beep if there is adequate continuity. Be sure that there is no nearby noise and that you are within adequate range of the multimeter to hear if it does beep. If the multimeter does not beep, this means that there is bad continuity in the circuit. This could indicate a blown fuse or an open switch, which may need to be shut or replaced.

Step 9

Check for blown fuses or open switches and replace as needed. Check continuity with the multimeter to see if continuity is restored.