If you are an electrician, you are probably quite familiar with multimeters and could use one with your eyes closed (except for the part about having to read what the multimeter says). However, like most people, though, you may have never even known what a multimeter was until you found out that you needed one to test your car’s or home’s electricity. This article will help you understand everything you need to know about multimeters so that you can purchase one with confidence that it will enable you to get the job done right.
Multimeters And Their Functions
What is a multimeter? A multimeter is a device, usually handheld, that measures values such as electrical current, voltage, and resistance.
What do multimeters measure? Multimeters measure many of the values that you probably learned about in high school science. It is also known as a volt-ohm-milliammeter because those are precisely some of the things that it measures. Volts are measures of the difference in electrical current between two different points; a measure of voltage, like what you see on traditional batteries, is basically a measure of how much energy is stored between the two ends. One volt of power is equal to one watt of energy (see below) to one ampere of current. (see below).
Ohms may sound like Eastern chants, but in this case, they are actually measures of resistance to an electrical current, how much something opposes the flow of electricity. The opposition needs to be at a certain level to prevent electrical malfunction (and potential fires or equipment failures!). An ampere, or amp, is pretty much the opposite of an ohm; it is a measure of conductivity, or how well electricity can flow through something. Amps are measured with milliammeters.
In addition to measuring volts, ohms, and amperes, multimeters may also measure wattage. A watt is a measure of how much power or energy something uses; you may see a reference to wattage on your electrical appliances or even on your power bills. They may also measure farads, or how much electrical charge is stored; siemens, or how much electricity is being conducted; hertz, or the frequency (wavelength) of electrical current; and temperature. Some more advanced, professional multimeters may measure even more units related to electricity.
How do multimeters measure resistance? Multimeters have two probes, between which is virtually zero resistance, thereby allowing a free flow of the electrical current that is being measured. One is placed at one end of a circuit, and the other is put at the opposite end. The reading is displayed in terms of ohms. Always make sure that the circuit is powered off before measuring to avoid causing the circuit to short out.
How do multimeters measure the voltage? Multimeters measure voltage by determining how much energy exists at one end of a circuit as opposed to the other. To measure voltage, first, turn the multimeter on and set it to the highest possible voltage that you might expect to find. Then, take the black probe (the one set for a negative voltage) and connect it to the low end of the circuit, which, in some cases, may be the ground. Take the red probe (the one set for a positive voltage) and connect it to the high end of the circuit. You may have to adjust the locations of the probes, and the multimeter will give you a reading of the voltage. If you have never used a multimeter before, you may want to practice by using it on batteries.
What are multimeters used for? Multimeters are useful for DIY jobs that require an understanding of something’s electrical condition. One of the most basic tasks that they can fulfill is determining if there is any life in a drawerful of old batteries. You can use a multimeter to test the cells to determine if they are completely dead or if they can still power your remote control. With that in mind, you can even use a multimeter to assess the condition of your car’s battery before taking it to a mechanic.
If you have an old extension cord in your garage or workshop, and you don’t know if it will work effectively or if it will short out your power tools, you can use a multimeter to see if the current flows through it continuously. If it does, then your extension cord can still be used. If it doesn’t, then you need to find a way to recycle it.
If you are experiencing an electrical failure at your house – say, you turn on a switch, but the light doesn’t come on, even though you just put in a new light bulb – a multimeter can help you determine which wire is faulty. You would need to go to your breaker box, turn off the power supply, and use the multimeter to determine if the house’s electricity supply is reaching that switch.
There are plenty of other ways to use a multimeter, whether you are a DIYer or a professional electrician.
How do you use a multimeter? The most important thing about using a multimeter is not to be intimidated by all of the electricity jargon that you may encounter in the user’s manual. You may see dial settings that look like Greek letters (some of them actually are Greek letters) or weird abbreviations that you have never heard of before. All of these symbols represent an electrical unit that the multimeter is capable of reading.
You don’t need to have a professional certification with all of the technicalities there; instead, you just need to learn what each symbol means and approximately what number you should be looking for on the dial. For example, if you know that the voltage of a particular appliance should be 120, then you set the dial to the voltage symbol and see if the reading is at or close to 120. If it is, great. On the other hand, if it’s not, you have a problem and may need to call an electrician.
Using a multimeter also requires a basic understanding of the two probes that come with it. You need to know where to put them when making a measurement. Make sure that the circuit is powered off first and that you are not touching any live wires. Other than that, multimeters are pretty self-explanatory.
What Should You Look For in a Multimeter?
That depends on who you ask. A professional electrician will probably spring for a multimeter in the $1,000 range, one that has all the bells and whistles necessary to tackle any electrical job. A DIYer or amateur repair person can get a much simpler one that can still carry out all of the functions required for less than $20. In other words, what to look for when buying a multimeter depends on why you need to use it.
Amateur multimeters. Amateur multimeters are designed to get a DIY job done around the house, nothing more and nothing less. They can vary in price from under $20 to around $100, and their features typically include:
• Digital or analog screen to give you a particular management
• Ability to measure volts, watts, amperes, and ohms
• Testing probes/diodes with safety precautions
Professional multimeters. Professional multimeters have some pretty intense features that, if you need them, can justify the steep price tag (which can easily hit $1,000 or more!). In addition to those of amateur multimeters, these features can include:
• Thermal imaging to show where electrical “hotspots” are
• Data storage of electrical info for easy reference
• Data connection to workflow management tools
• Additional settings for things such as diodes and decibels
• Advanced calibration capabilities
• Accessories to fit a wide range of appliances and circuits
Analog or digital? Multimeters are generally of two types: analog and digital. A digital multimeter provides a numerical reading on a screen. An analog multimeter uses a needle to point to a particular value. Most multimeters are digital unless otherwise noted. Professionals may prefer to use an analog multimeter when working with a circuit that may have a rapidly fluctuating value.
Safety features. Like on any electrical tool, these are pretty much standard, but there are some things that you should notice. Anyone looking for a multimeter should look at the standard safety features that the device has, particularly concerning how the electrical current enters it. Be aware also of the AC/DC guidelines that come with it, and make sure that anytime you use a multimeter, you always power off the circuit first.
Note: If there has been a burst of electrical activity, such as a lightning strike or a circuit that shorted out rather theatrically, do not try to use a multimeter yourself because transients within the wires can cause an explosion. Call a professional who is trained to contain the dangers posed by transients.
Professionals, in particular, should look for:
• Transient protection, which can prevent a dangerous explosion
• A high steady state voltage range
• Overvoltage protection
• High creepage and clearance distances
Below are reviews of the best multimeters for you to look for.
Best Multimeter To Test Batteries: Enno Logic Digital Multimeter With Battery Tester
If you need a multimeter primarily to test batteries that you have laying around the house, then we recommend this one from Enno Logic. It performs all of the standard functions of a multimeter and also has a special connection for testing batteries. The digital display is easier to interpret than an analog one, and it measures voltage, current, and resistance for professional and amateur jobs. It is handheld and battery-operated, making it easy to use when there is no available power supply, and automatically shuts off after 15 minutes of inactivity to save power.
This multimeter is ideal to have on hand for when you need one. It doesn’t have any special fixtures – it does what it needs to do, no more and no less. The price tag is low enough to keep in a DIY toolbox so that when you need a multimeter, you have one. FYI, if you don’t use it regularly, make sure you remove the batteries to prevent damage from battery leakage.
• Comes with standard banana plug sockets to fit many different circuits
• Accurate within 1%
• Comes with a warranty
• Safety features prevent fuse boxes from blowing out
• Can only test batteries up to 9 volts so is unable to test a car battery
• Test leads have plastic as a safety feature, making testing current “hit or miss”
Best Multimeter To Test Car Batteries: INNOVA 3320 Auto-Ranging Digital Multimeter
Testing car batteries is a little bit different than testing regular batteries; most batteries function pretty much the same way, but the high voltage of a car battery requires some specialized equipment. This multimeter was explicitly designed for the task of testing car batteries, and it comes at a low enough price tag that you don’t need to be a professional to justify purchasing one. In addition to going up to 12 volts on checking batteries, it also has the standard features of a multimeter, such as measuring amps and ohms.
It is handheld and runs on one AAA battery, so it is ideal for use when the electricity may have gone out or when you need to take a measurement away from an electrical socket. It features an auto-range, which means that you don’t have to dial in the approximate range of amps, ohms, volts, etc. when using it. You can also use the LEDs for testing regular batteries. This multimeter doesn’t come with a case, but you can buy one separately.
• Able to detect battery leaks on 12-volt batteries
• Can measure circuit breakers without blowing a fuse
• Tests continuity
• Cannot be powered by rechargeable batteries; must use standard alkaline batteries
• The small dial may be clumsy for users who have bigger hands
• Auto-ranging feature may take a couple of seconds to calibrate
Best Multimeter To Test Continuity: Neoteck Pocket Digital Multimeter 8233D PRO 2000
Continuity tests are important to see if there is something within a wire or circuit that is preventing electricity from flowing through cleanly. If you need a multimeter particularly for continuity testing, this Neoteck pocket one is probably what you are looking for. It uses a buzzer to indicate continuity, so you won’t even have to worry about looking for a particular measurement there. It is handheld and battery-operated, so you can use it to measure continuity and other electrical functions virtually anywhere. It also measures capacitance (in farads) and frequency (in hertz), in addition to many of the standard measurements that multimeters make.
This multimeter uses an auto-range, so you do not have to set the approximate range of a value before making a measurement. It uses a backlight to ensure that you can see the digital display even in darkness, lets you know when the battery is low, and automatically powers off after a period of inactivity. It uses banana plug alligator clips to test diodes; they are outfitted with insulating rubber for safety. This is a great, budget-friendly multimeter to keep around for whenever a project calls for it.
• Can measure the voltage on a car battery (but not the current)
• Has a data hold to remember your previous measurements
• Does not measure charging or discharging current; trying to make a current measurement may blow the multimeter’s fuse
• The 9-volt battery that it uses may drain quickly
• Some users have expressed difficulty with the buzzing feature of the continuity tester
Best Multimeter With Clamp: Voltcraft Current Clamp Meter VC330
Some people prefer to use a multimeter that utilizes a clamp so that they don’t need to make contact with a wire or circuit to make a measurement. As such, clamps provide an extra layer of safety to using a multimeter. If you prefer to use one with a clamp, we recommend this one by Voltcraft. Additional safety features make it shock-proof, and a rubber coating provides protective insulation and a firm grip for your hands. Using the clamp means that you don’t have to separate or power off wires or circuits before making a measurement, and the backlight display makes reading measurements easy, even when no light is available.
This multimeter can be used with one hand and runs on two AAA batteries. It can measure continuity, resistance, capacitance, and voltage. An auto-range setting means that you don’t have to set the device to the approximate range of what you are measuring. The continuity checker beeps to indicate that there are no obstructions to the flow of current. A low-battery indicator and auto power-off both help to make sure that the battery lasts longer and that you know when to reload the battery. The data hold stores the memory of previous measurements.
• Can measure AC and DC with the clamp
• Small size can easily fit in a full toolbox
• Comes with alligator clamps for when the clamp is not practical
• Can check the charge on solar panels
• May take a few seconds to make a measurement
• Not powerful enough for testing car batteries
Best Multimeter For HVAC: Fluke 117/323 KIT Multimeter and Clamp Meter Combo Kit
Heating, ventilation, and air conditioning (HVAC) systems have their own unique needs when making multimeter measurements. For them, we are going all the way and recommending a top-of-the-line Fluke multimeter. This one is more expensive than some of the other ones, so it’s for people who really need to get the job done and are more than weekend DIYers around the house. It can be used by professional electricians who need a testing device, though, for the more intense work, they may need something that is designed to withstand transient charges. This multimeter would be ideal for a professional who specializes in appliance repairs, such as HVAC systems and other large appliances.
This multimeter performs a whopping 117 functions, including a thermometer to measure heat, non-contact voltage detection, a set of leads, and a separate unit that features a clamp. As its range goes all the way up to 480 volts, it can be used for some professional jobs, as well. It measures frequency up to 50 kHz and is sensitive enough to measure current in milliamps. It comes with a calibration certificate to ensure that you get the most accurate measurement possible. A magnetic meter hanging strap allows you to make a measurement hands-free so that you can use your hands for something else.
Just so that you know you are getting a good deal, depending on which model you choose, this multimeter comes with a 2- to 3-year warranty, offered by the manufacturer. It also has an automatic sleep mode to conserve power. It runs on AAAA batteries and is completely portable, so it is ideal for use in a garage or workshop that may not have an extra outlet. If you don’t have batteries, though, it can be plugged into a power source. It comes with its own carrying case, so it can be safely stored for extended periods without you having to worry about it getting damaged. If you purchase this multimeter to carry out high-quality repair work that does not involve high-voltage charges, then you will not regret your decision.
• The multimeter measures AC and DC voltage and amps
• Low input impedance means that you won’t get a false reading due to ghost voltage
• Quickly delivers a high-accuracy reading
• The clamp meter doesn’t meter DC voltage so is not suited for automotive work
• Does not offer transient protection, so not for use by professionals dealing with potentials of high charges
• Does not have a Bluetooth connection or data storage, which may be necessary for higher-end professional jobs
Best Multimeter To Measure Current: AstroAI Digital Multimeter
Not all multimeters have the ability to measure current, as the charges could easily blow a fuse either in the meter or in the circuit being measured. If you need a multimeter specifically for the job of measuring current, we recommend this one by Astro AI. It is affordable enough to be used by a regular DIYer and has enough functions to be able to assist with numerous electrical projects.
This multimeter can measure continuity, voltage, resistance, current, frequency, capacitance, and temperature, as well as to test diode transistors. Its auto-ranging function makes measurements easy because you don’t have to input a potential range. It also has a professional setting that makes measuring AC voltage and current safer and easier.
• Makes a large number of measurements for a budget-friendly price
• Measures both AC and DC
• Beeps to indicate continuity
• Measures electrical functions in a range suited for an amateur, not a professional
• Lithium battery may be difficult to replace
• Display backlight only stays on for about 15 seconds
Best Multimeter With Capacitor Tester: Honeytek A6013L Capacitor Tester
If you get a budget-friendly multimeter, you can expect that it does either a wide variety of functions to a range that works for amateurs and DIYers, or it does a few tasks very, very well. In regards to capacitor testing, the Honeytek Capacitor Tester is pretty much limited to capacitor testing, but it does this one thing very, very well. It measures the capacitor’s resistance and the voltage that is stored within it, so it can indicate if a circuit within the capacitor is open, shorted, or otherwise defective. It measures up to 20,000 microfarads, and a few capacitors have a range beyond that, it can be used for amateur or professional jobs.
This capacitor tester runs on a 9-volt battery and has an LCD digital display with a backlight. It has built-in protection for input overload so as not to blow a fuse, and it will indicate when it is over-range. Its data-hold capabilities mean that it can remember previous measurements, and it will show when the battery is low.
• Contains ports for probing
• Makes quick capacitor measurements
• Compact size fits easily in a toolbox
• Not suited for in-circuit capacitors
• Won’t indicate if the capacitor can withstand the voltage that it contains
Best Multimeter To Measure Voltage: Klein Tools 69149
This multimeter kit is specially designed to measure voltage, as it can measure both AC and DC voltage with a safety rating of CAT III 600 volts. It can also measure DC and resistance, making it ideal for automotive work, including testing car batteries. As it is a kit, it comes with a three-pronged outlet tester, a complete multimeter, and a pen-shaped voltage tester. The NVCT-1 voltage pen flashes red and emits warning tones when the voltage is detected.
The multimeter has a digital screen with a backlight and can make many of the standard measurements that multimeters make. It also tests continuity by producing an audible noise when continuity is detected. The outlet tester can identify common problems associated with faulty wiring and indicates that the circuit is in good shape with LED lights.
• Can measure volts in decimals, giving a high degree of accuracy
• Works with both 110 and 220 voltage
• Measures AC and DC voltage
• Does not test microfarads
• Leads do not have alligator clips; they must be purchased separately
• Does not read amp hours
Best Multimeter With Data Connection: Extech EX542 Wireless
When you get into higher-grade electric work, you may need a multimeter that has a data connection so that you can easily store and access information from previous readings. This multimeter from Extech has a data acquisition mode that transmits information directly between the device and your personal computer. It is definitely in a higher price range so is better suited for someone who will need this data logging capability.
This multimeter performs all of the standard functions that you may need when making electrical measurements and can be used by professionals for many jobs. It can run on both an electric power cord or with batteries, but the batteries may be difficult to replace. It is double-molded to be waterproof, so it will be able to handle plenty of wear over its lifetime. It also comes with a three-year manufacturer warranty in case you have any problems with it. Additionally, if you order it from Amazon, tech support is included.
• Measures DC and AC voltage to 100 volts
• Measures both DC and AC
• Measures temperature from -58F to 1382F
• The battery may be difficult to replace
• Will require special software on your computer to run the data connection
Best Multimeter For Professionals: Fluke 87V/E2 Industrial Electrician Combo Kit
This Fluke multimeter comes with a steep price tag that corresponds with its professional-grade capabilities. It comes with different filters to help you measure a wide range of voltages with a high degree of accuracy, up to 1000 volts with both AC and DC. It measures up to 50 megaohms and 9,999 microfarads, as well as temperatures from -328F to 1994F. An input alert warns when you are using the wrong input cables. It comes with alligator clips, heavy-duty test leads, and test probes, as well as other accessories. A magnetic hanger allows you to use the device hands-free. All of its features are commercial-grade, so it is ideal for a professional electrician. It comes with a lifetime warranty.
• The temperature probe works in water
• Measures as low as 0.1 microamps of DC
• Can be used with both automotive and household tasks
• Does not require calibrating
• You may have to buy separate accessories for specialized tasks, such as measuring unopened circuits
• Does not measure picofarads
• Measures 20 amps for a short amount of time due to potential overheating