How To Use A Voltmeter: Two Easy Methods To Get You Started

How to Use a Voltmeter: Two Easy Methods to Get You Started

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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 If you want to check how much electric current is available in a certain electric device or an outlet, you will need a voltmeter. However, you may not get the correct readings if you do not know how to use a voltmeter. Therefore, this article will give you a step-by-step guidance on measuring voltage using a voltmeter so you can easily and safely check the voltage passing through the cables.

What is a Voltmeter?

A voltmeter is an electric device used to measure voltage of electricity present in outlets. It tests electronic circuits and components if they are working well. It also registers the difference between electricity present in two nodes of a circuit.

AC and DC

AC and DC are the two types of electrical current. Alternating Current (AC) s what you see on your home walls that connect to all of your plugs. AC changes the direction of flow and sometimes alters in voltage. AC has a considerable range and is suitable for use to transmit power over longer distances.

Direct Current (DC) flows in one direction and does not alter the voltage. Solar panels and batteries produce this form of current. DC is simpler and also very easy to use on smaller devices. However, it cannot travel very far.

How to Use a Voltmeter

Using a voltmeter is simple, but because there is always the first time to everything, we shall take a step by step procedure and learn how to use a voltmeter. Keep reading. There's a lot to learn.

A). Method One

Let's proceed and learn how to use a voltmeter.

1. Connect the Probes to the Voltmeter

There are two probes, one red and another one black. Connect the black probe to the negative connector, marked by a minus (-) sign. The red probe goes to the positive connector, marked by a plus (+) sign.

2. Select the Type of Measurement

Choose the correct setting for the type of measurement you want. For example, if you want to test a car battery or a battery used in the household, you measure the direct current; therefore, select the DCV setting. However, use the ACV setting if you want to measure the alternating current in your wall outlet.

3. Choose the Appropriate Range Setting

DC Voltage and AC Voltage have a variety of voltmeter settings. So, determine the range of voltage for the device you plan to test. But how do you do this? I'll give you an example. If the device you plan to test functions at 12V, set the voltage range between 10 and 14 volts.

4. Turn on the Voltmeter

Once you get the settings, find the on and off button and switch the voltmeter on.

5. Test the Equipment

Use rubber or plastic insulated handles to hold the voltmeter. Then, connect the probes to the right connector, the red probe to the positive and wire and the black one to the negative end.

6. Check the Reading

A digital voltmeter will display the reading on the screen, while the needle will show you the voltage output if you are using an analog voltmeter.

It is simple, so now you have your readings and have even learnt how to read your voltmeter; how cool.

B). Method Two

As you will see below, a multimeter measures voltage, ohms and amperage. Therefore we shall learn how to use a multimeter as it is also used to measure voltage.

1. Set the Meter

Because we have decided to use a multimeter with different settings, you need to ensure that it is set to get the reading you want. So, first, choose the AC or DC voltage setting; this will depend on what you want to read.

Set the range of the voltmeter slightly above what you expect. That is, if your outlet is 120V, set the meter to 200V. Power tools have the voltage marked on them, so you will not have difficulty figuring out the voltage. If you are unsure about the voltage of an outlet or the power tool, simply set the device to the highest setting.

2. Test Leads

There are two wires, one black and another one red. Each has a probe on one end and a jack on the other end. Put the back jack into the port labelled "COM" or common. The red jack goes into the port labelled V. If your multimeter does not have such a port, insert it in the one marked mA or one with the lowest number.

NOTE: The test leads are protected. However, ensure you don't touch the metal on the probes and do not let them touch each other.

3. Insert Probes

You will use the probes to measure the voltage present.


The black probe goes into the larger slot on the outlet. This is usually found on the top left; most black leads have a bump on them. Therefore, you can insert it into the outlet and let it go. The lead will stay well in place.

Next step involves taking the red lead and inserting it into the vertical slot. From there, you should be getting a reading. If your voltmeter reads "OL", it means that you are overloading it. So, you will need to remove it quickly before it gets damaged. If you get a reading showing that you are overloading the meter, simply raise the voltmeter range and reinstate the red lead.


The negative and positive poles are usually marked, making the process a little easier than when using an outlet. All you have to do is set the multimeter to read for DC or V- and then put the red lead on the positive terminal and the black lead on the negative terminal.

Sometimes you may get a DC+ 0r DC-on the voltmeter. If this happens, do not worry, simply change it to the other setting. You can also exchange the positions of the red and black leads. If that still does not work, you may need to drop the voltmeter's settings and repeat the process.

Voltmeter Vs. Multimeter

1. Voltmeter

As already mentioned previously, a voltmeter is used to measure the potential difference between two points or the potential of a single point. A voltmeter is usually a variation of a galvanometer. So, when you set a very high resistor in series with the galvanometer.

i). Analog Voltmeter

The heart of a voltmeter is a coil of fine wire suspended in an external magnetic field. The electrical current being measured flows through and reacts with this magnetic field, making it spin. The easiest way to measure voltage is using leads that connect to the power source of the device you are measuring.

Once your connection is set, the DC voltage works through the magnetic field and causes the coil to spin. The spinning then causes the stick on the analog voltmeter to rotate, showing a current reading in volts.

ii). Digital Voltmeter

A digital voltmeter uses sophisticated measurement technology; it has a LED display that shows the readings. Digital voltmeters have more resistance to outside magnetic interference while measuring circuits. Due to this resistance, digital voltmeters are more accurate and durable as they do not use a coil that may get damaged at any time.

When using a digital voltmeter, it is important to know that they take longer to make updates. Because a digital voltmeter takes longer to update, it is not easy to identify fast changes s it with analog voltmeters.

2. Multimeter

Like voltmeters, multimeters are also used to measure the voltage of a current. However, they also test and measure ohms and amperes, respectively, the resistance and current units. It is a collection of all meters possible. From its name, "multi", it is easy to tell that it measures many variables.

You can press the face of a multimeter to choose the parameter you want to measure, as well as the range. For example, you can have 0 to 2000 Ohms, 0 to 20 V, 0 to 200 mv and so on; this means that a multimeter is more versatile and flexible. They are also accurate so that you will get your measurements in precise units.

Advantages of Digital Voltmeters

Digital meters have more advantages over analog meters, and that is what we shall discuss now.

a). Accuracy

Digital meters do not use arrows to show the reading. Therefore, you don't have to have difficulty figuring out the value at which the needle is pointing. Instead, a digital meter shows precise computer-generated reading, which it then displays on a screen for you to read.

The digital-meter processors are dependable, and you don't have to make any calculations when reading the scale. However, the accuracy of an analog meter highly depends on the reader's competency to read analog meters. With digital voltmeters, the lack of parallax error enhances the accuracy because the reading can be taken from any angle.

b). User-Friendly

One of the best things about digital meters used to measure voltage is calculating and displaying the exact reading. This makes them very user-friendly. To get an exact reading, you will need to place the needle where the reading will be taken, then wait for the meter to display the reading.

c). Portable

Digital meters are more portable than analog meters, which are bigger. You can easily carry a digital voltmeter around and not feel the weight of n object. However, with an analog meter, you will notice that you are carrying something because f the bigger size.

d). Time-Saver

You are probably wondering why and how a digital voltmeter saves time. It's simple. When using an analog voltmeter, you will have to adjust to "zero-reading" after taking every reading. This ensures that your next value is not altered so that you can get an accurate reading. However, when you use a digital voltameter and even when you use a multimeter, you don't have to reset the device; this means that you will save a lot of time.

Disadvantages of a Digital Voltmeter

The coin always has two sides. Therefore, since we have seen the advantages of digital voltmeters, why don't we consider the disadvantages of the meter?

a). May Damage Easily

If you are using a digital voltmeter and the voltage increases beyond its limit, you may have to plan to buy another meter. This is because the high voltage may damage your meter, rendering it useless.

b). Measuring Fluctuations

The best thing about analog meters is that whenever there is slight fluctuation, the meter measures them. The needle will constantly swing to represent the fluctuations. However, with digital meters, you don't get to read the slight fluctuations in the reading. Instead, it represents the fluctuation as a whole reading or

Frequently Asked Questions About Voltmeters (FAQs)

1. How does an analog voltmeter measure the current level?

Analog voltmeters use various means to measure current levels, and d'Arsonval moving coil galvanometers are the most common. They use a coil of fone wire suspended within a magnetic field. This coil rotates to move a pointer or any other indicator proportional to the applied current level.

2. What should I do if my voltmeter is not working?

If you are in the process of measuring a DC circuit and you fail to get results, look for a small knob or switch on the device labeled DC+ and DC- then move it to the other position. If your device lacks this option, you may have to reverse the positions of the black and red probes. You can also reduce the range by one setting and repeat if you have to until you get a reading.

3. What can a moving coil galvanometer be used for?

The moving coil galvanometer is a highly sensitive instrument. Due to its high sensitivity, it can be used to detect current in any given circuit.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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