How to use a multimeter

Multimeter Use

If you’re doing any kind of electrical work—no matter what the application is—one of the best tools you can have at your disposal is a multimeter. If you’re just getting started, here’s how to use one and what all those confusing symbols mean.

If you're doing any kind of electrical work, no matter what the application, a multimeter is one of the best tools you can have at your disposal. If you're just getting started, here's how to use it and what all those confusing symbols mean.

In this guide, I’ll be referring to my own multimeter and using that as our example throughout this guide. Yours might be slightly different in some ways, but all multimeters are similar for the most part.

Throughout this guide I will be referencing my own multimeter and using it as an example for this guide. Some of your meters may be slightly different, but most multimeters will be similar for the most part.

this $8 model, which comes with everything you would need. Or you can spend a bit more cash and get something fancier, like this one from AstroAI. It comes with an auto-ranging feature, which means you don’t have to select a specific number value and worry about it being too high or low. It can also measure frequency and even temperature.

You can get something basic, like this $8 model  , which comes with everything you need. Or you can spend a little more cash and get something a little more advanced, like this one from AstroAI  . It has an auto-ranging feature, which means you don't have to pick a specific numeric value or worry about it being too high or too low. It can also measure frequency and even temperature.

battery symbol.

Your multimeter may also have a dedicated setting for testing the amperage of AA, AAA, and 9V batteries. This setting is usually represented by a battery symbol.

Again, you probably won’t even use half of the settings shown, so don’t get overwhelmed if you only know what a few of them do.

Likewise, you might not even use half of the settings shown, so you won't be overwhelmed if you only know a few of them.

How to Use a Multimeter

For starters, lets go over some of the different parts of a multimeter. At the very basic level you have the device itself, along with two probes, which are the black and red cables that have plugs on one end and metal tips on the other.

First, let's look at some of the different parts of a multimeter. At the most basic level, you have the device itself, and the two probes, which are black and red cables with a plug on one end and a metal tip on the other.

The multimeter itself has a display at the top, which gives you your readout, and there’s a big selection knob that you can spin around to select a specific setting. Each setting may also have different number values, which are there to measure different strengths of voltages, resistances, and amps. So if you have your multimeter set to 20 in the DCV section, the multimeter will measure voltages up to 20 volts.

The multimeter itself has a display on the top that gives you the readout, and a large selector knob that you can turn to choose a specific setting. Each setting can also have different numerical values ​​that measure different strengths of voltage, resistance, and amperes. So if you set the multimeter to 20 in the DCV section, the multimeter will measure voltages up to 20 volts.

Your multimeter will also have two or three ports for plugging in the probes (pictured above):

The multimeter will also have two or three ports for plugging in the probes (as shown in the image above):

• The COM port stands for “Common”, and the black probe will always plug into this port.

  COM port stands for "Common" and the black probe will always be plugged into this port.

• The VΩmA port (sometimes denoted as mAVΩ) is simply an acronym for voltage, resistance, and current (in milliamps). This is where the red probe will plug into if you’re measuring voltage, resistance, continuity, and current less than 200mA.

  The VΩmA port (sometimes indicated as mA VΩ) is just an acronym for Voltage, Resistance, and Current (in milliamps). If you want to measure voltage, resistance, continuity, and current less than 200mA, you plug the red probe in here.

• The 10ADC port (sometimes denoted as just 10A) is used whenever you’re measuring current that’s more than 200mA. If you’re not sure of the current draw, start with this port. On the other hand, you would not use this port at all if you’re measuring anything other than current.

  Whenever you measure a current greater than 200mA, you use the 10ADC port (sometimes indicated as 10A). If you are unsure about the current draw, start with this port. On the other hand, if you are measuring anything other than current, you will not use this port at all.

Warning: Make sure that if you’re measuring anything with a current higher than 200mA, you plug the red probe into the 10A port, rather than the 200mA port. Otherwise you could blow the fuse that’s inside of the multimeter. Furthermore, measuring anything over 10 amps could blow a fuse or destroy the multimeter as well.

WARNING: If you want to measure a current greater than 200mA, make sure you plug the red probe into the 10A port instead of the 200mA port. Otherwise, you may blow the fuse inside the multimeter. Also, measuring currents greater than 10 amps may blow the fuse or damage the multimeter.

Your multimeter might have completely separate ports for measuring amps, while the other port is specifically just for voltage, resistance, and continuity, but most cheaper multimeters will share ports.

Your multimeter may have a completely separate port for measuring amps, and another port dedicated to voltage, resistance, and continuity, but most cheap multimeters will have shared ports.

Anyway, let’s get started actually using a multimeter. We’ll be measuring the voltage of a AA battery, the current draw of a wall clock, and the continuity of a simple wire as some examples to get you started and familiar with using a multimeter.

Anyway, let's start actually using the multimeter. We'll measure the voltage of AA batteries, the current draw of a wall clock, and the continuity of simple wires to get you started and comfortable with using a multimeter.

Testing Voltage

Start by turning on your multimeter, plugging the probes into their respective ports and then setting the selection knob to the highest number value in the DCV section, which in my case is 500 volts. If you don’t know at least the voltage range of the thing you’re measuring, it’s always a good idea to start with the highest value first and then work your way down until you get an accurate reading. You’ll see what we mean.

Start by turning on the multimeter, inserting the probes into their respective ports, and setting the selector knob to the highest number in the DCV section, in my case 500 volts. If you don't at least know the voltage range of the object you are measuring, it is always best to start with the highest value first and work your way down until you get an accurate reading. You'll see what we mean.