Hey! Hope you are doing well and enjoying your life. This post is all about how you can use a multimeter to measure a resistance of any resistor that you come across.
I suggest, to learn quickly and efficiently, grab your multimeter and some random resistors that you have and go along as you read the post, apply what you read and this will stay in your minds forever (I tell you! 😊).
If you do not own a multimeter and don’t know what to buy and from where?
I have quick suggestions for you. They have all the basic features you will require as a newbie and guess what, they are affordable as well. If you want to learn in detail about these multimeters, you can visit the post here.
- 1 Resistance measurement for beginners using a digital multimeter
- 2 Resistor setting on a digital multimeter
- 3 Step by step guide to measure resistance using a multimeter
- 4 Quick tips to remember
- 5 An insight into my personal experience as a newbie (My Story)
- 6 Summary
Resistance measurement for beginners using a digital multimeter
A resistor is the most fundamental electronics component that you encounter a lot in your life as an engineering hobbyist or engineering student.
These tiny components are hidden everywhere in all the electronics devices that you see around you.
So, how to know what resistance each resistor is offering?
You might or might not have, in your life, already used a multimeter to measure the resistance of a given resistor. In this post, I will share some basic knowledge about how you can measure the resistance using a multimeter if you are a complete beginner.
Also, I will be sharing some quick tips and tricks for all of you, whether you have used a multimeter or not. These quick tips will be your friend all your life (You can thank me later when you use them)
Resistor setting on a digital multimeter
Every multimeter is different in its settings from the other one. The basic settings of all the multimeters fall into two categories.
- Auto range
- Manual range
For all the multimeters, you will observe the sign of “ohm” (Ω) somewhere on your multimeter. This is where the knob of your multimeter should point when you wish to measure resistance using a multimeter.
The Auto-range multimeters have only one setting or point where you will point the knob of your multimeter to measure resistance. I’m sharing the following image for your reference here.
If you have such multimeter, know that you are working with an auto range multimeter.
For the manual range multimeters, there is a single ohm sign and then there are multiple ranges defined under it. You can choose from all the given ranges according to your need.
See the above for reference. If your multimeter’s settings panel looks like this, you are having a manual range multimeter.
Auto-range v/s Manual range
While we are already on the topic of Auto-range and manual range multimeter settings, why not discuss a little deeper to know, which one is better and why?
Since we are already living in the world of automation, we are addicted to it. We like automation more than anything.
Same goes with multimeter settings.
The auto-Range multimeter will not bother you at all, you just put the probes across the resistor and it will give you a value right away.
Seems pretty easy right??
On the other hand, while dealing with a manual range multimeter, you will have to keep rotating your knob to get to the right setting or range for your resistor.
This can be pretty tricky in the beginning as you yourself will experience sometimes if you are using one. Sometimes you are expecting a larger resistance value, but your multimeter gives a small value and you later figure out, you were working in a wrong setting all this time.
So, in short, auto range multimeter will save you lots of time and energy in your life.
Step by step guide to measure resistance using a multimeter
Now that we already have had a detailed introduction about resistance measurement settings on a multimeter, let’s dive into our actual goal, measuring resistance using a multimeter.
To measure your resistor value using a multimeter, all you will need is your multimeter, and the resistor you wish to measure the resistance of. So, grab your material and let’s get started.
You start by turning on your multimeter (Obviously!!!)
1. Connecting the probes
Connect the multimeter probes to the correct terminals. You might wonder at this point what the correct terminals are, right? Let me tell you in more detail. Look at the image below.
Most multimeters have three or four terminals and 2 probes. If you look closely, you will observe that each terminal is labeled. The most common labels in multimeter are COM, VΩmA, and 10A. The COM terminal is the common terminal or ground. The VΩmA, as it indicates, is voltage, ohm, and milli-amps port. Which means you can measure voltage, resistance and small currents using this port. So, for you, the correct terminals will be the COM and VΩmA terminals. Yes, you guessed it right. Connect the black probe in the COM port and the red probe to the VΩmA port.
2. Tunning your multimeter into OHM meter
Now that you have connected the probes, you need to turn your multimeter into ohm-meter, i.e a device that measures resistance. To do so turn the knob of your multimeter to Ω sign.
If you have an auto-range multimeter, you don’t have to worry much. But if own a multi-range multimeter, you need to find the suitable range for the resistor you have chosen.
3. Measuring the resistance value
Connect the probes of the multimeter to the legs of a resistor, one probe would be on one side while the other one is connected to the other side.
It is important to note here that a resistor has no polarity, so it doesn’t matter which way you connect your probes to the resistor, the value of resistance will be the same.
Another important point here is for the people using a multi-range multimeter.
You must start from the minimum range of resistance for your multimeter. If your resistance value is bigger than this range, you will observe ‘OL’ value written on the screen.
Switch to the next range and observe the value, if the same reading appears, increase the range of resistance again until you observe a numeric value on the screen. The OL value means “overload”, which means the multimeter is unable to measure the value of the resistor in the selected range.
Sometimes this may happen that you are operating your multimeter in larger ranges and your resistor value is too small to be detected in that range. In such cases, the multimeter gives a ‘0’ value.
This means for this range, the value of resistance is nearly zero, or immeasurable. For such cases, you need to step down the range and observe the values.
In other cases, you might know a rough estimate of resistor value say 200 ohm and you measure the value and it comes out to be around 0.2 on the screen.
In such cases, double check that you have your multimeter in the correct range because you will see that your multimeter was in the range of kilo-ohms and this is why your reading was too low.
After reading such a lengthy story, you must have realized why I said earlier that auto-range multimeter is more convenient.
4. Verification of measured resistance value
You can double check this value by computing the value using the color bands of the resistor. If you know the color bands, you can do it yourself manually.
For those of you who don’t have any idea about color coding of resistors, can go check out the post on resistor basics here.
But if you still want a simpler solution, you can always consult google where you will find numerous color code calculators. Just input the color of your bands and they will do the math for you.
Now you will encounter some situations where your resistance is not exactly what the color code is telling. Don’t worry. The resistance can vary a bit in some specified range depending on the tolerance value of the resistor.
It can be more or less than the actual value practically. All you have to worry about is, the value must be closer to the actual value, if not exactly the same.
This is all you have to do to measure the resistance value using a multimeter.
Quick tips to remember
Let me summarize the tips for measuring the resistor value using a multimeter for you here.
- Make sure to connect the probes of multimeter correctly. Double check for surety because you may damage your multimeter if you are not careful.
- While using a multi-range multimeter, always start from lowest range and increase your range according to your need until you get a numeric value.
- Remember, a resistor is a non-polar device, so you don’t need to worry about which probe is to be connected to which side of the resistor. You can always confirm this statement by checking the resistance in both the directions.
- Resistance can vary a little bit from its exact value. The measured value must be closer to the exact value.
An insight into my personal experience as a newbie (My Story)
This might or might not interest you, but let me share my personal experience with you. When I first learned to measure the resistance of a given resistor, I was taught 2 methods together, the color coding and by using a multimeter.
To my bad luck, I was provided with the multi-range multimeter in the lab and I had to work with it. I was told I was supposed to only connect the probes across the resistor and it will give me the value.
Sounds easy right??
But not in my case, my multimeter was not set in the right range and I had no idea about it.
Everyone else in the class was measuring the resistance and was happy to have it measured so easily, but my multimeter showed ‘OL’ on the screen and I was too afraid to ask my teacher about it.
So, I told my friends, I think my multimeter is not working properly, see, instead of showing the value of a resistor, it gives me ‘OL’ message.
Since we all were first semester students, we thought the same and we didn’t, tell the teacher about it in the fear that I might have damaged the multimeter.
Since I was a very curious child and was always playing with the devices, pressing their buttons and all, I started to turn the knob. The teacher started to take round and check the students if they were working, after having turned the knob, just to pretend I was working,
I connected the probes to resistor again. To my surprise, a value appeared on the screen. I called my friends again and told them the multimeter is now working fine, I have measured the resistance now.
The lab ended that day and I was happy just to know the fact that multimeter was not damaged at all. It was only later in the course that we learned about the fact what ‘OL’ actually meant.
Let me summarize all the story for you here. To measure the resistance of a given resistor, follow the following steps.
- Set your multimeter in the resistance measurement settings.
- Choose a suitable range.
- Connect the probes of the multimeter across the resistor.
- Always double check the values using color codes, or online color code calculators.
- You don’t need to worry about connecting the probes in the wrong direction, there is no wrong way of connecting the probes to a resistor for measuring the value.
- Always make sure to connect the probes on the multimeter in the right ports.
This is all I want to share about, resistance measurement for beginners using a multimeter. Hopefully, it has helped you in some way. If you any question leave it in the comment section, share it with your friends.
Thank you and have a good life.
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Special thanks to
Engr. Tuba Tanveer, MS Electrical Engineering from National University of Science and Technology (NUST), Islamabad