How To Use A Multimeter To Check Continuity

How To Use A Multimeter To Check Continuity

Ian Mutuli
Updated on

 A multimeter is a must-have tool to test, diagnose, and troubleshoot electrical circuits and components. The multimeter is primarily used to measure the voltage of devices, measure current, and measure resistance. In this write up we are going to show you how to use a multimeter.

Mostly we are going to help beginners who are not aware of what is required of them when it comes to using a multimeter. First, we will give a rundown of using the analog, flake, and digital multimeter, how to use the multimeter to measure current, voltage, and resistance in a circuit board, and measuring continuity.

What is a Multimeter?

A multimeter is also referred to as a volt-ohm meter (VOM) or a multitester, and it is a fundamental tool for examining if electrical devices are working properly or not. It is used to measures voltage, current/ amperage, and resistance. The multimeters come in two main types, analog and digital type.

If you want to learn and understand how to use a multimeter, you must understand the main parts of the volt-ohm meter to know how to use it correctly. You need to pay attention to three main parts of a multimeter: the display, selection knob, and ports.

The display will usually be an LED display that will help exhibit the measurements after testing the voltage, resistance, or current. The selection knobs are the dials or buttons that allow you to set the test meter that you want depending on what you are testing.

The ports are usually on the front of these devices. Most of the multimeters have three ports,  continuity test mode or COM, 10A, and mAVΩ. COM or continuity test mode is used to measure the circuit or component, 10A/20A is used to measure voltage, and the mAVΩ is used to measure resistance.

A multimeter is a very easy-to-use tool usually used by electricians to maintain or troubleshoot motors, appliances, circuits, wiring systems, and power supplies issues. However, it is important to understand that these tools can be extremely dangerous, and they will require you to have the right knowledge while using them. Therefore, to help you learn how to use a multimeter properly, we have prepared a few steps you could use to help you use a multimeter efficiently.

1. Measuring Voltage

You could use a multimeter to measure voltage. For example, if you have the digital multimeter, you could use it to measure both dc voltage or ac voltage, but the analog multimeter will only measure alternating current.

The volt-ohm meter will usually have a section that is marked V, which stands for voltage. You measure the voltage of electrical devices to see if they are working properly. There are few basic steps that you could follow while measuring the voltage.

a) DC Voltage Steps

To measure DC voltage, you will only need to follow a few steps, and you will need to be super careful.

  1. Turn the multimeter dial on to V with a straight line, which stands for voltage to measure DC voltage. You will turn the voltmeter using a button usually located in the lower-left corner of most multimeters. Remember V with a straight line means DC voltage, and V with the wavy line stands for AC voltage.
  2. Plug the red probe and the black cable into the corresponding voltmeter switch to measure the voltage. This means that you plag the red probe top the red port or volt jack and the black cable to the black port or volt jack.
  3. Then connect the test leads to the power supply circuit. Here you will have to ensure that your hands do not come in contact with the lead tops. Additionally, it is also important that you start with the black probe then the red probe. Remember, you can measure the Dc voltage drop across components like the resistor.
  4. Determine and measure dc voltage. The multi-meter will have a display that will indicate the measurements. In case the multimeter reads a negative value, this means you have electrically connected the probes to the wrong terminals. Therefore, red should always go with the positive terminal and the black probe to the negative terminal.
  5. Once you are done, ensure that you remove multimeter probes starting with the red probe.

b) AC Voltage

With the AC voltage, you will have to be super cautious, and it is best to use it by professionals or use it under an expert's supervision.

  1. First, you must ensure that your probes are perfectly and correctly plugged into the ports or terminals. Note that you should not touch the probes and that there is no exposed metal. Remember that the AC is super dangerous.
  2. Turn the knob or dial on to V with a wavy line that represents the AC voltage measurement. Always set the knob to the V before you plug the red probe or the black probe. Remember, you can measure the Dc voltage drop across components like the resistor. Remember V with a straight line means DC voltage, and V with the wavy line stands for AC voltage.
  3. Plug the black probe and the red probe into the main power supply. Remember to be super careful while doing this.
  4. Now read the measurements indicated on the screen.

2. Measuring Current

Measuring current can be more complex since you need to measure it in series. To measure voltage, you will use voltage, but in this instance, you will use current, which means you will have to disrupt the current flow and ensure that the meter is in line to get accurate readings. If you wonder how to use a multimeter to test current, we have prepared a few steps to help you out.

  1. Turn on the multimeter to measure current.
  2. Plug the black probe and the red probe correctly. The black probe should go first with the continuity test mode or COM socket, and the red one should go with the high current or the mA/ 10A/20a switch.
  3. Then turn the knob on the volt-ohm meter to the highest current range to measure current.
  4. Turn on the power. Remember, if the range is too high, you need to switch to a lower range to get more accurate readings.

3. Measuring Resistance

You can measure resistance between two points to access or determine the condition of your components like resistor or circuit. Always remember low resistance means the higher the current flow and vice versa. To measure resistance, we have indicated the few steps you could use.

  1. First, you have to ensure that you turn off the circuit power.
  2. Turn your multimeter knob to resistance or ohms. The display will indicate OLΩ once it is in the resistance mode.
  3. Then connect the probes, the black probes will go to the continuity test mode or COM port, and the red probes into the VΩ jack. Remember to put the black cable first and the red second, and when removing, start by removing the red probes from the COM port followed by the black one.
  4. Then turn the dial to the lowest Ω or ohm range.
  5. Connect test probes tips across the component like resistor being tested and read the readings on display.
  6. Always remember to turn the multimeter off when you are done.

Types of Multimeter

Basically, there are three types of multimeters, Analog fluke and digital ones. The digital and the analog multimeters are the most commonly used types. To help you understand better, we have discussed the three types.

1. Analog Multimeter

The analog multimeter is usually designed using a shifting coil meter and a pointer to show the readings. The analog multimeters are used to measure voltage, current, resistance, frequency, and signal power.

An analog meter is relatively cheap but is usually very hard to use and is not the best option for beginners since it can be hard to take accurate readings, particularly on a voltage and resistance test. The basic use of the analog multimeter is to measure the electrical potential in resistance, ohms, and volts. Additionally, they can be used to test if there are any short circuits or components like resistor issues.

The more advanced analog meters have amazing features like a capacitor, diode, great battery power, overload protection, mirrored scale, range switch, and IC testing styles. Moreover, most of them will have diode tests and battery tests. For example, a device with a diode symbol will test diode operation, and those with a battery test will test the battery operation. However, they will also have many manual settings and multiple scales on dials that are hard to use and read.

2. Digital Multimeters

Digital multimeters or DMM are the most commonly used meters today. These meters may be more expensive than the analog versions, but they are easy to use. A DMM will function well for both DC voltage and AC voltage and will provide accurate readings.

The DMMs usually have two probes, which are positive and negative, which usually come in two colors, red and black, respectively. In addition, the DMMs feature an LCD, knob, and analog to digital converter. The printed circuit board or PCB in the DMM has concentric rings that will disconnect or connect depending on the position of the knob.

A digital multimeter can test a variety of parameters within an electrical circuit. The basic DMMs can test amps, volts, and ohms with ease compared to analog ones. Many of the DMMs will have enabled functionality like they can be used while testing capacitance, frequency, transistor functionality, and continuity of a circuit temperature,

3. Fluke Multimeter

Fluke digital multimeter is a great multimeter commonly used and comes with a combination of different functionalities. The fluke multimeter is protected against transient voltage and features a larger screen that will indicate the readings.

The Fluke is mostly used to measure the voltage, current, and resistance between two points. However, you will also find some other Fluke multimeters that will be used to measure duty cycle, humidity, frequency, temperature, diodes, among others.

Tips About Using A Multimeter

If you have learned how to use a multimeter, there are some tips we have prepared that will help boost the safety and help you the multimeter like a pro.

  1. First and foremost, you should know and remember that you should be super careful while handling or using a multimeter.
  2. You must get a good and high-quality multimeter that will handle the kind of job you want to be done. This will help get accurate readings and will reduce the risks of getting injured.
  3. Before you start using the multimeter, ensure that it is in good working conditions. For example, you could check if the knobs are shrouded and not cracked or damaged. Also, you could check to see if the connections are firm as you insert them into the ports.
  4. Always return the multimeter selection knob to read voltage after use. You will need to return the probes to the voltage port and set the multimeter.
  5. Ensure that when measuring both AC voltage and DC voltage, the probes are always connected to their respective ports correctly while measuring voltage.
  6. Ensure you turn your multimeter off each time you are done using it.

Frequently Asked Questions on How to Use a Multimeter

1. What is a multimeter used for?

A multimeter is a standard tool used to test electrical values by showing the voltage, current, and resistance which are also commonly referred to as volts, amps, and ohms, respectively. Mostly the tool is used by technicians in the electric industries but could still be used in our homes.

2. What is the easiest multimeter to use?

Today's market has many great options of easy-to-use multimeters, and it can be daunting to get one that suits you best. The Fluke 115 compact RMS digital Multimeter is one amazing choice that you could opt for. This multimeter features great features that are user-friendly and is a great option for beginners.

3. Which is dangerous, AC or DC?

In most cases, the A.C or alternating current is considered more dangerous than D.C or direct current. The AC is known to be five times more dangerous, and its frequency of 60 cycles can cause severe effects on your body and even kill a person.

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.