What Does OL Mean on Multimeters? A Beginner’s Guide


As an electrical engineer from Stanford University with over 7 years of experience using multimeters.

If you have ever used a digital multimeter, you know that it can be a little overwhelming at first. All those numbers and symbols on the screen can make your head spin! But one particular symbol seems to cause more confusion than the rest: “OL.”

When you’re testing an electrical component and see “OL” pop up on the screen, it can be pretty confusing. I mean, what does it even mean? Well, fear not! As an expert in electrical testing, I’m here to help you understand exactly what “OL” means on a multimeter in different tests and modes.

So take a deep breath and relax. We’ll figure this out together.

Let’s get started!

What Does OL Mean On A Digital Multimeter? In voltage and current modes, “OL” typically means that the meter is overloaded and cannot read the value being measured. This may happen if you’re trying to measure a voltage or current that is higher than the range your meter is set to. In this case, you’ll need to adjust the range to get a valid reading.

What Does OL Mean On A Multimeter

So, what exactly does “OL” mean on a multimeter? Well, it turns out that “OL” is actually an abbreviation for “Open Loop.” This can mean different things depending on the type of test you’re running and the mode your multimeter is in.

In general, “Open Loop” means that there is no continuity between the positive and negative probes of your multimeter. This could be because the circuit you’re testing is open, or because the voltage in the circuit exceeds the test limit of your multimeter.

Now, I know this might all sound a bit technical and confusing but don’t worry! I’m here to break it down for you.

To start with, let’s think of a circuit as a plumbing system. In this analogy, the current running through the circuit is like water running through a pipe. The conductive metal in the circuit is like the pipe that carries the water from one end to another.

So, when your multimeter displays “OL,” it’s like there’s a break in the pipe somewhere, and the water (or current) can’t flow through. This could be because the pipe is broken or because there’s a valve that’s shut and preventing the water from flowing.

As we go on, I’ll explain more about what these different scenarios could mean and how you can interpret “OL” readings on your multimeter.

Explanation of OL in Different Tests And Modes

Now that we have a basic understanding of what “OL” means on a multimeter, let’s dive into some specific examples of how it can be used in different tests and modes.

OL Means Before Attaching Probes

You might have noticed that whenever you turn on your multimeter and don’t connect the probes to a testing component, an “OL” reading is always displayed on the screen. But why is this?

Well, it’s because until the probes are connected, there is no complete path for current to flow through. Just like a broken pipe in our plumbing analogy, the current can’t flow if there’s a gap in the circuit. The multimeter detects this open line and displays “OL” as a default setting.

Now, it’s worth noting that some multimeters might display a “1” instead of “OL,” but they both mean the same thing – there’s a discontinuity or break in the circuit. So, if you see either of these readings when you haven’t connected the probes, don’t worry – it’s perfectly normal!

OL Means When Testing Continuity

When testing for continuity, a continuity test checks whether electricity can flow through a conductive path uninterrupted. If there is an interruption between two points in a circuit, then there is no continuity. In this case, the multimeter screen displays OL, indicating that there is an opening or break within the loop, hence the term “Open Loop”.

For example, if you’re using a multimeter to test a wire for faults, an OL reading means that there is a problem with the conductive copper between the points where you’ve placed the negative and positive multimeter probes. This interruption of the path between these two points means there is no continuity, just like how water won’t flow through a broken pipe.

OL Means When Testing Resistance

To measure resistance, you need to set your multimeter to the Ohms setting, represented by the Greek letter Omega (Ω). If the multimeter shows an OL or 1 on the screen means there is no continuity in the path. In other words, the circuit or component being tested has infinite resistance, or the circuit is broken or disconnected.

OL Means When Testing Voltage

When you use a multimeter to measure voltage within a circuit, it’s important to set the dial to the correct range. If the voltage exceeds the range you’ve set, the meter screen will display “OL”, indicating an “overload”.

For example, if you’ve set the dial to the 2-volt range and the voltage within the circuit is more than 2 volts, the multimeter will display OL or 1, which means that you need to adjust the dial to a higher range.

The same thing happens when measuring high or low currents. In some cases, the meter may display “1” instead of “OL”. In either case, the solution is to adjust the multimeter to a higher range for accuracy.


Well, folks, that was a crash course on what “OL” means on a multimeter. We’ve learned that OL stands for “Open Loop” and indicates that there is no continuity between the positive and negative multimeter probes, or that the voltage in a circuit exceeds the test limit.

From testing continuity to measuring resistance and voltage, OL can have different meanings depending on the mode of the multimeter and the type of test being performed.

But fear not, because armed with this knowledge, you’ll be a pro at reading your multimeter screen in no time. Just remember to adjust the range on your multimeter dial to avoid OL, and to always make sure your multimeter leads are properly placed.

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