Digital multimeters are an important part of many professions and hobbies. If what you’re doing is related to electricity in any way, chances are you’ll use a multimeter at some point. But once you’ve bought a multimeter, how do you make the most of all the features it has to offer?
In this article, we’ll go through the basics of using your multimeter. Chances are your multimeter will be able to do all these basics, but not every multimeter will look the same. After reading this article (or while), spend some time with your digital multimeter’s manual to find where you can find specific features on your model.
Design of a digital multimeter
Although each model of digital multimeter will look slightly different, they’re all set up the same way. There is a display at the top where you can read the measurement’s results, there is usually a round dial to select different types of measurements, and there will be some probe connectors (similar to an audio jack you’d hook a pair of headphones up to) that hold the test probes.
To execute most measurements, you’ll need to hook up the test probes to the digital multimeter using the probe connectors. Not every measurement will use the same combination of probe connectors, so make sure you familiarize yourself with each unique setting.
Basic features of a digital multimeter
Not every digital multimeter will have the same features. Some can measure temperature, perform diode tests, or measure specifics about car engines. If you’re looking to use your digital multimeter for a specific purpose, make sure you buy one that serves that same purpose.
But just as a multimeter’s design has a standard setup, there are some basic features that are present in every multimeter. In short, the three measurements that almost every multimeter will allow you to do, are continuity, voltage, and resistance. As we mentioned before, there is a chance your specific multimeter differs slightly, but as a general guideline, these will be standard features on your digital multimeter.
Testing continuity with a digital multimeter
Continuity testing is one of the main functions of a digital multimeter, and many people will buy one just for this feature. A good electrical circuit is an uninterrupted line from point A to point B. Testing continuity means nothing more than testing whether that line is indeed uninterrupted, or if there is a break in a wire or circuit. It can be used to test a switch or a fuse.
Before you test, make sure that there is no current going trough the object you’re testing. Then, put your black probe in your multimeter’s COM port, and the red probe into the port marked VΩmA. Next, select the continuity setting with the dial on your multimeter. If your model doesn’t have a dedicated continuity setting, select the lowest ‘resistance mode’ setting. This sends a small signal through the test object and sees if it comes through okay.
With the probes in place and the correct setting selected, first push the metal ‘leads’ (the ends of the probes) together. The display should measure close to 0, and if your model has a continuity setting, you’ll probably hear a beep. This means you’re ready to test your object.
To perform the test, place each probe at one end of the object you’re testing. If there are no problems in the object, you’ll again see a value on the display around 0 and you may hear a beep. Test complete!
Testing DC voltage with a digital multimeter
Another common test with a digital multimeter is testing DC voltage. There are two types of voltage (AC and DC), but because this is a beginner’s guide, we’ll stick with DC voltage. This is the type of voltage that you’ll find in household electronics, anything that runs on batteries, and batteries themselves. AC voltage is the kind of voltage that your house’s electrical circuits are made up of, and therefore much more dangerous (and less suited for a beginner’s guide).
To start the test, place your probes in the same ports as we did with continuity testing; the black (negative) prompt in the common port indicated with COM, and the red (positive) prompt in the VΩmA port. Select the DC voltage meter function on your multimeter; it is displayed as a V with one straight line and a dotted line right under it. If you have a manual multimeter, you’ll also have to select the voltage range of the object you’re about to measure. For example, if you’re measuring a 1.5V AA battery, you’d select the 2V range.
Next, place one lead on one end of the object, and the other lead on the other end. After a while, the reading should be displayed on the display section of your multimeter. It is not that important which end you use the positive and negative prompts; if the leads are reversed, the reading will display in the negative (but still be the same value).
Testing resistance with a digital multimeter
Our last test is a resistance test. You’d want to carry out a resistance test to analyze the condition of a circuit or object. The higher the resistance, the less of a current flow there is. Resistance is measured in ‘Ohms’ and is displayed with the Ω symbol on your multimeter’s dial. If you’re not sure about the range, start in the highest setting and work your way down from there.
Testing resistance looks a lot like the other tests. Your probes go in the familiar ports, so black in the common port, and red in the VΩmA port. Once you’re ready, put each of the leads on opposite ends of the test object and wait until the display settles on a number.
In this article, we’ve looked at the basics you’ll find in any digital multimeter. We’ve discussed design, features, and the three main functions of using a digital multimeter. Most multimeters will offer additional features and functionalities, so make sure you dive into your model’s manual as well to discover all that your digital multimeter has to offer!