How to Use a Digital Multimeter

So, you want to measure the resistance or voltage of the pumps, sockets, and other things around your house. How should you get started? Read on to learn more! 

​About Multimeters

Before everything else, you may want to know more about multimeter and its beneficial uses. 

A digital multimeter (DMM) is a useful device mainly used for measuring resistance, voltage, and current as well as for checking fuse and wire continuity. It is also known as a volt-ohm meter (VOM). If you love DIY jobs such as troubleshooting an electrical or electronic component, the multimeter is such a handy, useful accessory to be added in your home toolkit. Electronic industries and technicians are the main benefactors of this tool. 

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Analog meters were replaced by the digital multimeter because of its ability to provide a much higher level of accuracy and reliability. The first multimeter was first introduced by Fluke in 1977. It is usually composed of 4 components: (1) display where you can see the measurement readouts; (2) buttons which allows you to choose from different functions (note that options vary from one model to another); (3) input jacks in which test leads are attached; and (4) rotary switch or dial if you need to choose between ohms, volts, and amps to perform a particular task. 

There are digital multimeters of all sizes and shapes. Each has its own certain functions. Regardless of the type of multimeter you use, there are some basic practices about the electrical properties measurement that we want to tackle. 

Remember:

It is imperative to know the different symbols in a multimeter:

Volts DC (=) – the most commonly used setting for automotive applications. Specific readings rely on the electrical component status and the circuit. 

Volts AC (~) – emits AC current that is rectified by the diodes within the regulator. 

Ohms – the third most utilized value on the multimeter. You can use it if you need to test most sensors. 

Amperage – the most dangerous value. Most of the units are available in detached lead port for amperage, with the limited number of amps a unit can be able to measure safely. 

Continuity – the symbol varies by digital multimeter manufacturers. It is very useful if you want to find poor grounds, open or short circuits, damaged wires, etc. 

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How to Use the Digital Multimeter for Voltage Measurement

Use the voltage to measure various things around your house, including the microwaves, pumps, and sockets. 

1. Set up the mode to V with a straight line (V=) if you want to measure the DC voltage and to the V with a wavy line (V~) if you wish to measure the AC voltage.
2. The red probe must be ensured to connect to the port with a V following to it. 
3. Measure the AC voltage by putting the probes in the right wall socket slots. Otherwise, measure DC voltage by putting the probes both on the negative and positive circuit components. 
4. Read the DMM reading on display.
   

How to Use the Digital Multimeter for Resistance Measurement

Before starting, switch off the power of your component if it’s in an appliance or on the circuit board. 

1. Plug the red probe in the V slot while the black probe in the COM slot. 
2. Turn on the multimeter and then set the dial to resistance mode. Bear in mind that resistance is basically measured in Ohms. 
3. Test the amount of resistance by inserting the probes on the resistor. 

How to Use the Digital Multimeter for Current Calculation

Here, we determine the current of a circuit through measuring in amperage (amps). It is a unit of an electrical current that indicates the amount of electricity thatruns through a circuit. 

1. Place the red probe to a certain measuring socket (20 A for measuring bigger current and mA for measuring low current degree). 
2. Look for the Amp setting. Measure the current by turning the dial to it. 
3. Get your wire cutter to cut the wires (also called circuit breaking). 
4. Splice inyour DMM to get a precise reading. 

How to Use the Digital Multimeter for Diode Measurement

Want to check if the diode or LED in your circuit is in good shape? Perhaps, your curiosity kills you about the color of your LED when powered. This is where the diode mode comes handy. 

1. Insert the red probe into the V slot and the black probe in the COM slot. 
2. The regulator knob must be adjusted to the diode symbol. 
3. Now, put the black probe on the LED cathode while the red probe should be on the anode. You must notice a glow in your LED. 

How to Use the Digital Multimeter for Fuses and Continuity Check

Continuity testing identifies if a closed or open circuit occurs in an electrical/electronic device or appliance. You can even use it for sensing broken wires and bugs likefaulty wires. 

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It is one of the most useful multimeter tests for electrical or electronics repair. Before getting started, make sure there is no current functioning through the component or circuit you plan to test. Remove the batteries or switch off the power supply. 

1. Insert the red probe in the V slot and the black probe in the COM slot. 
2. Let’s say you’re checking continuity between terminals (Terminal A & Terminal B), put one probe on Terminal A and the other one on Terminal B. 
3. You will know if there’s a connection between the two terminals if you get a continuous “beep” sound and the meter reads zero. On the contrary, you won’t be able to hear any sound at all if there is no connection emergingor if the component or circuit you are testing has a  faulty connection. 

Your Safety is Highly Important!

DMMs are impulsive tools. Hence, proper safety precautions must be taken into account when handling any electrical measurements. Refer to the manual first to understand the accurate operating procedures, restrictions, and safety precautions before using electrical test equipment.