How to Use a Digital Multimeter

A very useful tool for swiftly determining voltage, resistance, continuity, and current in a variety of electrical circuit types is a digital multimeter. Once you know what the different symbols on the dial mean, using a digital multimeter is really simple. You’ll soon be using your digital multimeter to test various gadgets by reading the Being Sunnies blog!


Measuring Voltage

Test leads should be inserted into the COM and V terminals. Always insert the black test lead into the “COM” (for “Common”) terminal. Since you are evaluating voltage, always connect the red test lead to the terminal marked “V” for “Voltage.”
In this case, the test leads detect both AC and DC voltage.

Set the dial to the appropriate voltage for either AC or DC voltage. When measuring AC voltage, set the dial to V or V with a wave symbol next to it. To measure DC voltage, set the dial to V or V with a horizontal line next to it.
Things you might find around the house, such as wall plugs, microwaves, and other home electrical appliances, are measured using AC, or alternating current, voltage.
For the most part, batteries are measured using DC, or direct current, voltage. In addition, many small gadgets and automobiles use DC voltage.

Set the predicted voltage range to a greater voltage. You won’t receive an accurate measurement if you set the voltage range too low. Look at the dial’s numbers and select the setting that is just over the expected voltage of the object you are measuring, but is also the closest to it.
Set the dial on 20V, for instance, if you’re measuring a 12V battery and your multimeter has settings for 2V and 20V.
Simply set the multimeter to its highest voltage rating if you are unsure of the voltage of what you are reading.

Connect the probes to a load or a power source on either side. Place the black probe’s tip, for instance, into the right side of a wall socket or the negative lead of a battery. For example, insert the red probe into the positive side of a wall socket or the positive end of a battery.
Put a probe on either end if you’re unsure of which is positive and which is negative, and then check what the multimeter says. Your positive and negative are reversed if it’s a negative number.
When placing the probes next to a wall socket, keep your fingers away from the probe tips to prevent electric shock. Avoid letting the probes touch one another to avoid creating a short circuit that can result in an electrical fire.
Always grasp the probes by their insulated, coloured handles to avoid receiving a shock.

View the voltage reading on the multimeter’s display. You’ll obtain a reading on the multimeter that indicates the voltage of what you’re testing once your probes are linked to the positive and negative leads. To find the reading, look at the digital display and, if required, make a note of it.
You can detect if the voltage you’re monitoring is average or not by looking at your reading. For instance, if you measure the wall socket and the multimeter displays a reading of 100V, this is lower than the average of 120V, indicating that the voltage in this wall socket is low.
When testing a brand-new 12V battery, the voltage reading should be close to 12V. The battery needs to be checked if it is lower or not reading at all.


Testing Current

Turn the dial to Amps and insert the test leads into COM, A, or mA. Enter the COM terminal with the black plug. Depending on the amperage of the object you are measuring current from, insert the red plug into the A or mA, labelled amps or milliamps, respectively. Turn the multimeter’s dial to the Amps setting to find it. [6]
Most multimeters include two amp terminals: one for currents up to 10 amps (10A) and one for currents up to about 300 milliamps (300mA). Put your red plug in the amps terminal if you’re unsure of the amperage range you’re measuring.
If necessary, you can always change to milliamps for a more accurate result. One A for alternating current (used for domestic power and denoted by the wave symbol) and one A for direct current are found on some multimeters (used in batteries and wires and represented by a horizontal line with a dotted line under it). The most common type of current utilised in this reading is direct current.

Disconnecting one of the circuit’s wires will shut off the circuit. This enables you to finish the circuit and measure the current using your multimeter as an ammeter. Remove one wire from the terminals it is attached to on one side of the circuit by unplugging it or another method, leaving the other wire attached to its terminals.
Whichever side of the circuit you disconnect doesn’t matter. The goal is simply to create a gap where your multimeter may be spliced into the circuit in order for it to function as an ammeter and inform you of the amount of current flowing through the circuit.
In order to measure the current flowing straight through the wires, you must “splice in the multimeter.”

To read the current, touch the leads of the multimeter to the open terminals. To splice the wire into the circuit, attach 1 probe to each of the terminals you just disconnected it from. To find out how much current is passing via the circuit, read the screen.
Which probe you touch to which side of the circuit doesn’t matter. In either case, your multimeter will give you a reading.
Electrical circuits can be troubleshot by inserting your multimeter into various parts of them. If you get a lower current reading in one part, there may be a faulty wire blocking the electrical passage.
Test milliamps instead of amps if your first measurement of 1, for example, is extremely low.


Measuring Resistance

Place the red test lead in the terminal and the black test lead in COM. Insert the COM terminal’s plug into the black test lead. The red test lead’s plug is inserted into the terminal denoted by the letter “ohm,” which stands for the unit of resistance measurement.
The sign is probably connected to the V sign, indicating that the terminal used to monitor both voltage and ohms is the same.

Set the dial to a resistance reading on the multimeter. On the dial of your multimeter, look for the sign. Set the dial to a position that is near the anticipated resistance in this section. Set it to a value at the top of the scale if you are unsure of the anticipated resistance. Until you obtain an accurate reading, you can change it as you measure.
The obstacle to the flow of current in an electrical circuit is known as resistance. Low resistance is exhibited by conductive materials like metal while high resistance is exhibited by non-conductive materials like wood.
Set the dial to slightly above 0 to gauge a wire’s resistance, for instance. You can check online or in a manual for the anticipated resistance for various electrical components. Depending on the particular model of multimeter you have, the figures on your multimeter could be anything from 200 and 2 million ohms.

Read the resistance by placing the probes on the resistor. Place the probes’ tips on either end of the resistor. You can see the reading, which indicates the resistance in ohms, on the multimeter’s digital display.
If your multimeter just displays the number “1,” you might need to turn the dial to raise the value of ohms being measured in order to get a more accurate result.
If necessary, jot down the reading while noting the appropriate unit.


Testing Continuity

Remove the batteries or unplug the appliance you want to test. You cannot check for continuity while the gadget is still powered on. Before continuing, make certain that the device is unplugged from all power sources.
Your multimeter’s continuity feature can be used to check whether or not wires are still functional. Measure the continuity of a cord or wire if you’re unsure of whether it still has a solid connection. This examines the relationship between two circuit points.
A continuous electrical flow route indicates continuity. A brand-new electrical wire, for instance, needs to be completely continuous. It lacks continuity, though, if it is frayed or damaged because electricity cannot pass through it. This is a useful method for determining whether internal cable damage exists.

Connect the probe wires to the multimeter and select continuity on the dial. Connect the red plug to the terminal marked with a V,, or a continuity symbol that resembles a sound wave. Enter the COM terminal with the black plug. Select the image that resembles a sound wave by turning the dial.
A sound wave resembles a progression of progressively larger (“”) symbols.
The continuity option only displays 1 sound wave, not a range of numbers. To make sure the dial is positioned correctly, turn it until it is directly pointed towards the continuous sound wave.

The ends of the component you are testing should be connected to the probes. Put the red probe on the other end of the component and the black probe on one end. In order for the multimeter to function properly, be sure that both probes are simultaneously touching the ends.
To check for continuity, the component does not need to be unplugged from the circuit.
Which probe you place on the component’s end is irrelevant.
You can check the continuity of components including wires, switches, fuses, and conductors.
To check for continuity, you must touch two conductive ends. Consider placing the probes on two bare wire ends.

As a robust connection is indicated by a beep, pay attention to it. If the wire is functioning properly, you should hear a beep as soon as the ends of the two probes touch. You have a short in the wire if you don’t hear a beep.
Your wire may be short if it has been burned or cut.
You can infer from the beep that there is essentially no resistance between the two spots.

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