What Is a Multimeter and Where Can You Use It?

A multimeter is an electrical measuring instrument that is used to measure several electrical properties, such as current, voltage, resistance, and frequency.

Depending on how advanced the multimeter is, you can also conduct continuity tests, diode tests, and temperature measurements. Some advanced multimeters even have infrared thermometers to measure temperatures from a distance.

Let’s explore the different types of multimeters available, how they work, and what you can do with them.

How Do Multimeters Work?

A multimeter is a device that combines multiple circuits into one. A multimeter that measures current, voltage, and resistance simultaneously functions as an ammeter, voltmeter, and ohmmeter. A simple turn of the circular knob on top of the multimeter will switch it from voltage measurement mode to current measurement and more.

You can measure direct and alternating voltages separately with a multimeter, and the same goes for current. Therefore, one unit would be sufficient to measure current in household outlets (AC) and car batteries (DC).

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To test any parameter, connect the testing probes to the jacks of the multimeter and attach the other ends to the circuit to be tested. Make sure the multimeter circular knob is pointed towards the correct parameter before testing anything.

After measuring the parameter, the multimeter will display its output as an analog or digital reading depending on which type of multimeter you are using.

If you've never used a multimeter before, get familiar with the multimeter symbols first. They are standard and so will be exactly the same on any multimeter produced by any brand.

Types of Multimeters

Based on their output display, multimeters are categorized into two types: digital multimeters and analog multimeters. Let's briefly discuss each.

1. Analog Multimeters: As the name suggests, analog multimeters are old-fashioned meters that display the measured value with a needle on an analog scale.
2. Digital Multimeters: Digital multimeters convert the analog input into digital and display the measured value in digit form.

It's easier to take quick readings with digital multimeters. Also, measuring data with a digital multimeter is more precise than with analog ones. Therefore you should go with a digital multimeter if you are just getting started.

Digital Multimeter Options

With a digital multimeter, you have two further options: you can choose a handheld multimeter or a larger benchtop one. In addition, you need to decide whether the multimeter should be auto-ranging or not.

• Auto-ranging Multimeters: Modern multimeters are usually auto-ranging, which means they can automatically switch their ranges depending on what value they measure.
• Manual-ranging Multimeters: With these you will have to adjust the range yourself to suit what you’re measuring. That reduces accuracy and adds to the workload.

Clamp Meters

For testing small circuits, a standard handheld or benchtop multimeter is perfect. If the current through your appliances is high enough to be harmful to measure with a multimeter, however, a clamp meter is your best option.

Detecting the magnetic field around a single wire allows the clamp meter to take the correct measurements. In fact, live wires can also be tested with the help of clamp meters. A clamp meter differs from a multimeter in that there is no direct connection between the circuit and the meter.

Applications of Multimeters

Here is a brief overview of the different applications of multimeters.

1. Automotive Inspection: Automotive service is one of the main applications of multimeters. With a multimeter, you can measure battery charge, run a leak test on its cover, test the alternator, and inspect the car horn or any other electrical circuit in your system. Many high-end units, such as the Power Probe IV, are capable of testing fuel injectors, PCM/ECM drivers, and signal tracking. It's a must-have gadget for automotive technicians.
2. Household Applications: Every home should have a multimeter. Testing faulty sockets, checking continuity, inspecting home appliances, and testing the rest of the circuits in the house are made easier with this device. Even though no brand specifically designs multimeters for home use, any multimeter capable of measuring basic parameters would work.
3. Industrial Applications: Multimeters can be used in a myriad of industrial applications. Several engineering tasks require using multimeters, such as measuring the temperature of instruments, conducting continuity tests, evaluating current flow, or analyzing circuits via infrared imaging. A few modern multimeters are even capable of sending live feeds wirelessly.
4. DIY Applications: DIY electronic project enthusiasts also use multimeters extensively. The multimeter makes it easier for them to perform experiments at home. Basic multimeters are most suitable for DIY project applications, as no high-end testing is required. As a result, they are relatively cheap in comparison to other applications.

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Safety Tips to Use a Multimeter

Here are a few tips you should follow while using a multimeter:

1. Always choose the right meter for the job.
2. Hold the multimeter by the insulated handles.
3. Avoid measuring sources that are outside the range of your meter.
4. While using a manual range multimeter, adjust the range carefully.
5. Always wear your protective gloves.
6. Don't use a multimeter when the fuse is blown.
7. Check the CAT ratings of your multimeter.
8. Inspect the multimeter and its probes physically.
9. Calibrate your meter regularly.
10. Never use a multimeter on an exposed circuit.
11. Avoid testing circuits in a humid environment.
12. Store your multimeter in a protective case.

Multimeter Internal Safety: Multimeters from well-known brands typically include fuses that protect their internal circuits when the current exceeds their maximum capacity. These fuses break when a high current surge occurs. Instead of buying a new multimeter, you will only need to replace the fuse.

Multimeter Cost

Multimeters range in price from $50 to thousands of dollars. So, before buying a multimeter, you should clearly define what your needs are and make the right choice for them.

For basic home testing or school experiments, a less expensive multimeter would be sufficient. In contrast, if you need to test high-end HVAC appliances or conduct industrial inspections, you will have to get a more expensive multimeter.

Even in the latter case, buying a multimeter doesn't need to break the bank as you can obtain a fully advanced multimeter for less than $1,000.

Get Your Hands on a Multimeter

A multimeter is an excellent tool for detecting electrical faults and is relatively safe to use. In a few days, you can become familiar with it. Be careful not to become careless, though. Always consider taking professional advice where necessary.

While performing creative and easy DIY projects, make the multimeter your best friend.