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Working with circuits or other electrical components can be dangerous without the right tools. Luckily, there’s a specific tool that makes these kinds of projects safe and easy. Said tool is the multimeter, which is versatile, accurate, and reliable.
But what is multimeter, exactly?
If you’re not sure why a multimeter is an excellent tool, these are some of the the things it’ll help you find out.
- Whether a switch is on.
- Whether the wire is conducting electricity or not.
- The current that flows through a circuit.
- How much power batteries have left.
- The multimeter can answer all of those questions and more.
Now you see why this is a must-have tool for electricians! And I bet you’d love to learn more about it, too. So, continue reading this guide to find out everything there’s to know about this fantastic tool.
What Is A Multimeter Used For
A multimeter is a tool used by technicians to measure different electrical quantities. This includes current and voltage as well as resistance.
To gather this measurement, you must connect the multimeter to a circuit or component via the test probes. Shortly after doing that, the device’s processor will convert the power received into a digital value. Then, it displays this information through the screen.
All of that happens in seconds, which is why the multimeter is such an efficient tool.
Types of Multimeter
The process described above is true only to multimeters classified as digital models. For analog multimeters, the procedure is slightly different.
Analog multimeters show amperage on a graduating scale, which uses a traditional pointing needle. While this design is somewhat outdated, many people still prefer analogs because of their affordable price.
If you want a digital multimeter, be ready to spend a bit more money.
All of the money put into a digital multimeter pays off in the long run. In addition, these multimeters are modern, easier to use, and super accurate. Thus, it’s a tool that appeals to both professionals and beginners alike.
What Are the Parts of a Multimeter?
Knowing what makes a good multimeter will help you while buying one. Let’s go over the different parts of this tool to understand a bit more how it works.
This is clearly one of the very first things to notice about the multimeters. Commonly found at the front top side, the screen shows the current or voltage picked during your tests.
Of course, the screen of an analog multimeter is a bit different. Unlike the digital that shows digital values on an LCD screen, analog meters have a pointer that aims to the voltage value.
This is commonly a knob, or a dial found right in the front center of the unit.
The purpose of this feature is to help you choose a function to measure something. In some cases, it can be voltage, but it can also be current in other models. With the control switch, you can also set the multimeter to read AC, DC, frequency, amperes, and much more.
Designed as insulated metal needles, the test probes allow you to check the presence of electricity in a circuit. You can do this easily by attaching the probes to the multimeter and then touching the circuit.
For an easier understanding of how each of them works, the probes come in different colors. Red is for positive, and black for negative.
And this is where the test probes go. These connections refer to three access points to connect the probes to the multimeter. The connections can be common (COM) or voltage/current.
Typically, the black goes into the common port while the red attaches to the voltage/current port.
More specifically, a set of batteries to power up the multimeter. However, some meters may have a plugging port because they receive electricity as the power source.
What Does A Multimeter Measure?
Let me preface this by saying that not all multimeters are the same. Some may be more capable than others, meaning not all of them have the same functions.
With that said, this list includes the common uses of a contemporary multimeter. You can use this tool for measuring the following:
- Voltage, represented in volts. This can be either alternating or direct.
- Current, represented in amperes. Like before, this can also be alternating or direct.
- Resistance, represented in ohms.
Multimeters can also measure:
Digital multimeters are also compatible for testing:
- Continuity, emitting an audible beeping sound if the circuit conducts.
- Diodes and transistors.
- Battery tests.
And these are only a few of the many things a multimeter can measure.
How to Use a Multimeter (3 Ways)
There are many applications for a multimeter. Nonetheless, I’ll keep this section short by talking about the most common uses for this tool. Let’s talk about how to use a multimeter to measure voltage, current, and resistance.
These steps are exclusive to digital multimeters.
How to Measure Voltage
Let’s start with voltage. You can use the multimeter to measure either DC or AC voltage. Each one comes with its own symbol, so pay attention to that.
- DC voltage, represented by a capital V with a straight line over it.
- AC voltage, represented by a capital V with a wavy line over it.
Tip: The multimeter used for these tests is the UNI-T UT90A multimeter.
To measure voltage:
- Turn the knob of the multimeter to your preferred setting. For example, if you’re testing AC voltage, set the testing mode to V with a wavy line. For DC voltage tests, set it to the V with a straight line.
- Get your probes ready, and connect the red one to the port that has a V symbol right next to it. The other end should attach to the component’s positive side. This is where the current comes from.
- With the COM probe attached to the multimeter, proceed to connect the other end to the other side of the component.
- Once the probes touch the component, the display will show the measurement picked.
Tip: Measuring voltage requires you to connect the multimeter in parallel. Doing this is pretty easy. Using the probes in parallel means placing them along with the leads of the components under test.
How to Measure Current
To measure current using a digital multimeter, follow the next steps.
- Turn off the power of the circuit you want to test.
- Make sure the probes are in their right socket. The black probe lead must go into the COM socket.
- As for the red probe, you can connect it to either the mA connection or the high current connection. The latter can have a 10A or a 20A label next to it. Some meters don’t have this socket, using the same one to measure current and voltage. In this case, the symbol would be VΩmA.
- To measure current, the correct method to use the multimeter is in series.
- Set the multimeter dial to the highest current range. If you’re using a multimeter with an auto-range function, turn it to the “A” or mA setting.
- Turn the power on.
- Check whether the range is too high. If that’s the case, start switching it to a lower range. This will give you a better and accurate reading.
- With the tests finished, don’t forget to put the positive probe back into the V socket. This is essential after measuring current. Basically, the meter turns into a short circuit with the lead is in the mA/10 A connection.
Be aware: Connecting the meter to a voltage source with the probes in this setting would mess up the meter.
How to Measure Resistance
Before starting a resistance test, you must prepare the equipment for safety first. This is what you have to do.
- Is the component under test part of a circuit or an appliance? If that’s the case, make sure to turn off the power first.
- If the component is part of a circuit, disconnect one of its ends. This procedure may require you to pull off spade leads or do some desoldering tasks. This is super important, so don’t dismiss it. Resistors or components can still have some resistance like the component under test.
- Your safety always comes first, so take the previous considerations seriously. Once you get the component ready and secure, you can now move forward.
- Start by connecting the probes to their corresponding connections.
- Go to the dial, and set it to the lowest Ω range. This symbol is for ohms measurements. The range should be approximately 200 ohms.
- Grab the test probes, and place their tips on both ends of the component you want to measure.
- In some cases, the display may show a value of “1.” If this is the case for your reading, you’re dealing with a resistance greater than the display can show under the current setting. Therefore, it would be necessary to change the dial to the following highest range.
- Continue doing the same until the display shows proper value.
How to Use Analog Multimeter
A bit more old-school, the analog multimeter has plenty of similarities with the digital multimeters but also significant differences. The biggest difference is the scale, which can be tricky to understand. Let’s clear that out briefly before jumping into the steps to use this type of multimeter.
The Analog Scale
Unlike digital multimeters, the analog has a scale for the readings. At the top, there’s a line that serves as the ohmic scale. While measuring resistance, this scale goes from left to right.
Depending on the range you selected, it’s necessary to multiply the scale reading with the previously established range. For example, if the pointer needle stays steady at five with the range set on 1k, the correct reading would be 5k ohms.
Under the ohmic scale, you’ll find the scales for voltage and current. Again, there’s a black line that measures DC voltage as well as current. Additionally, the red line is specifically for AC readings.
Other than that, the analog multimeter works much like the digital multimeter. Follow the same steps but keep in mind the following considerations.
To Measure Volts:
Grab the two test probes and allow them to touch the points of the circuit you want to measure. Keep in mind that volts represent the amount of pressure flowing through the electrons. Therefore, putting both probes on the same point would read zero volts due to no pressure difference found.
To Measure Resistance:
Turn off and disconnect the component out of the circuit. Since the meter operates on a battery, this battery can send a small current across the probes and right into the circuit.
To Measure Amps:
To measure amp, you must connect the meter to the circuit. Hence, some work like cutting or disconnecting may be necessary. This would allow you to make the meter another part of the circuit.
The analog multimeter can be challenging to explain. Check out this educational video to learn more about it.
Tips on How to Use the Multimeter Correctly
As with most other tools, there’s a particular technique needed to use the multimeter correctly. However, it isn’t as simple as just plugging the probes and touching a circuit. In fact, some tips and tricks may help you during all of your projects.
Put these tips into practice to make the most out of your analog multimeter.
Pick an Ideal Range
While you’re using the analog multimeter for measurements, be sure to choose the appropriate range. This may sound like a no-brainer, but people often dismiss it. As a result, the accuracy of the reading won’t be as good. For more precision, do this before and during each quantity measurement.
Using the tool to measure high AC voltage while set on DC function may cause irreversible damage. Worst case scenario, this is an issue that could render the device useless.
Speaking of safety measures, don’t forget to wear gloves while operating the multimeter. This tool is safe for the most part, but you also have to do your part to use it safely.
Calibrate the Multimeter
One thing about these meters is that they need regular calibration. Otherwise, the tool may not perform as good as it once did. So, make sure to calibrate the analog multimeter before any task. If you use this device regularly, you may want to calibrate it each week.
Check the Batteries
Like in most other tools that need batteries, the batteries are essential for optimal measurement performance. Therefore, don’t dismiss the quality of the batteries.
Instead, go for a top-notch set, and don’t forget to replace them when needed. Damaged batteries can cause a lot of fluctuations in your readings.
If you’re not sure about the value of the quantity you’re measuring, set the multimeter to the highest range.
Try Using a High-End Multimeter
For professionals, a high-quality multimeter may prove a better option. Don’t go for cheap models that may not offer as many functions a technician would need. Plus, consider buying a digital multimeter as well. These are faster, more accurate, and more durable. Though a bit more expensive, digital multimeters are worth it.
Follow the Alarm
Don’t underestimate the beeper/alarm of the multimeter. This is such a helpful feature that’ll make your readings much easier. For instance, the better lets you know if there’s zero or low impedance. As such, you’ll know almost immediately if those issues are troubling your circuit.
Frequently Asked Questions (FAQs)
With so much information about multimeters, you may have a question or two to make. So here we answer the most common:
Why is a multimeter essential?
A multimeter is an essential tool for electrical technicians and engineers. Used for decades, it has remained one of the most used instruments to test circuits, components, batteries, and more. Thanks to this fantastic versatility, this tool can serve multiple applications instead of just one.
The multimeter is crucial because it allows you to find existing faults in live circuits.
You can use it to measure voltage and many more functions with different modes. All of this leads to more and better proficiency while doing electric work.
You may get a multimeter for a particular task. However, you’ll find more and more uses for this tool as time passes.
Why is my multimeter not working?
There are three things to check if the multimeter isn’t working correctly. These are the battery, fuse, and connections.
Check the battery if the multimeter won’t turn on or is showing a dim display. This could mean that the battery is either week or entirely useless at this point. Fix the issue by replacing the battery.
The next potential issue could be the fuse. Open the multimeter, and locate the fuse. Check for blown fuses. If that’s the case, replace it.
If the issue is coming from corroded wires or connections, use a soldering iron to desolder the connection. Clean it if possible, and resolder it into place. You may also want to look for loose parts or lost screws.
What’s the difference between expensive and cheap multimeters?
Other than the price, the most significant difference between cheap and expensive multimeters is the quality of their components.
A clear example here would be the dial selector. In most cheap meters, this is one of the first things that break. Thus, operating the multimeter afterward would be nearly impossible.
Safety is also a concern while picking a multimeter. For high voltages, cheaper models could be a bit dangerous. Then again, this is something that only professionals would do using a high-end multimeter.
Luckily, cheap multimeters can be super accurate. This is the reason why they’re perfect for DIYers and beginners.
Can you damage a multimeter?
Yes, and this is an issue that happens more often than one may think. For example, using the meter to measure a quantity without the proper settings could cause the tool to get fried. And this is one of the least problematic scenarios. Without proper care, the multimeter can go as far as giving you a shock.
This is why proper maintenance and correct use of the multimeter are essential aspects of these tools. Not only because it’ll allow the multimeter to last longer, but also because it’ll be safer.
What to consider to buy a multimeter?
First, you must make sure whether you need a digital or analog multimeter. The cost of each one does vary.
Then, you want to go with a reliable brand. Fluke is one of the best, as their products are reliable and super accurate. Plus, the design of these tools is straightforward, making their use intuitive for beginners.
Lastly, consider whether the multimeter will meet your demands. Commonly, digital multimeters are the most expensive. But, they also happen to be more versatile. For regular DIYers or professionals that work with electricity daily, these are a must. They will allow you to tackle a variety of projects due to their versatility.
Learning what is a multimeter is a must if your purpose is to make the most out of this tool. And you should! Dealing with electric components can be dangerous, meaning that reliable tools are essential. In that regard, few are as trustworthy as the multimeter.
After learning a bit more about this tool, you’re now ready to start working on your projects. Remember to be as safe as possible and follow each of the steps described here. This will allow you to get accurate readings to operate circuits and equipment safely.