Your car tyre might go flat, you might have split wine on your very white carpet,  or you might have torn your favorite t-shirt, etc. 

But, fear not, there is good news! Lucky for you and me, there are tools that exist to help us solve and rectify these kinds of problems. 

This is no different in the electrical and electronic world. It’s inevitable that you are going to encounter problems.

So, having tools to help analyse these problems is a necessity to ensure that you aren’t stuck in the mud. 

One of the most common and widely used tools for fault finding, and analysis of circuits is the Digital Multimeter.

But, what is the use of a digital multimeter? Digital multimeters are electronic measuring instruments that are used for fault finding, analysis, and diagnosis of electrical and electronic circuits. They have the ability to measure electrical quantities such as voltage, current, and resistance. 

However, there is more to digital multimeters than meets the eye which shall be discussed in detail in this article. 

Closer look at a digital multimeter?

The digital multimeter is a variety (digital version) of the Multimeter. 

While the digital version of the multimeter is the most commonly used nowadays, it has come a long way from its humble analog beginnings.

A brief history of the analog multimeter

Analog multimeters, or earlier versions first showed up on the electrical scene in 1820. Back then they were known as Galvanometers. 

They were limited to only detecting electrical current, and resembled a compass which had a needle that moved depending on the amount of current. 

Fast forward 100 years, the first version of the modern day multimeter was created thanks to Donald Macadie. 

His multimeter wasn’t limited to just measuring current, but could measure voltage and resistance as well. 

How analog multimeters work

The fundamental workings of an analog multimeter is based around something known as a moving coil meter.

Measuring voltage, current or resistance, depends on the configuration of some precision shunt resistors (either in series or parallel).

While there are many versions of the analog multimeter, each having its own method of measuring voltage, current and resistance, the moving coil meter is the most widely used method. 

Analog multimeters have a needle (that is connected to a coil meter) and is deflected according to the amount of current that the coil meter is subject to. 

This comes to fundamental science, and the fact that current flowing through a wire generates a magnetic field. 

This is the basics of how the analog multimeter measures current. As mentioned earlier, to measure other variables such as voltage and resistance, additional components will need to be added (such as high precision shunt resistors).

Brief history of the digital  multimeter?

Unfortunately, with the advancement of technology, analog devices were being replaced by digital counterparts and this was no different for multimeters.

This was possible with the rise of Semiconductors. A solid state voltmeter was in the development phase as early as the 1950s. 

However, it wasn’t until 1977 when the Fluke 8020A became the first readily available digital multimeter. 

Over the years, with the cost of manufacturing decreasing, the digital multimeter started to make its way to the forefront and was the go to multimeter. 

The Fluke 8020B sold over 1 million units by the late 1980s. 

How a digital multimeter works

The most noticable difference between an analog and digital multimeter is the display. 

While an analog multimeter uses a needle that physically moves, the digital version uses a Liquid Crystal Display (LCD) that displays values of voltage, current and resistance. 

Also, there is no moving coil meter in a digital multimeter. 

They use integrated circuits such as operational amplifiers, Analog to Digital Converters (ADC), Digital to Analog Converters (DAC), Microcontrollers, and/or Microprocessors. 

Below are the sequence of steps that occur within a digital multimeter when it is subject to a current, voltage, resistance, etc at its input;

1. Input is converted to a DC voltage within the ADC range
2. ADC converts DC voltage to a digital value 
3. This values is displayed on the LCD screen 

The steps mentioned above are more common for measuring voltage. To measure current and resistance, the digital multimeter implements techniques similar to those used by its analog counterpart (using series and parallel shunt resistors). 

To measure current, voltage is measured across a known resistor. 

For resistance measurement, voltage is measured across a resistor via a known resistance from a stabilised voltage in the meter. 

Digital multimeters come equipped with a Positive (red) and Negative (black) terminals where multimeter probes are connected to. 

What is the main use of a digital multimeter

The digital multimeter is a very versatile tool and while it might have been restricted to a few functions in its earlier time, it has come a long way, and nowadays digital multimeters come packed with a myriad of functionalities 

So to eliminate confusion, I shall go through and give a description of each function and its overall uses. 

I shall break this section into two parts; functions of a digital multimeter and uses of digital multimeter in given applications using those particular functions.

Function #1 of a digital multimeter: Voltage 

The first most basic function of the digital multimeter is to measure Voltage.

Voltage is one of the three basic building blocks of any electrical and electronic circuit (current and resistance being the other two). 

Theory is only one half of the puzzle when building and designing a circuit. 

When it comes to the practical part of building the circuit, knowing that the values of voltage you calculated for in the design process match the voltages in the circuit you built is essential to make sure you are on the right track.

That is why a digital multimeter comes equipped with a function of measuring voltage. 

Voltage is the potential difference between two points in a circuit, so you will have to measure across a component or between two points in a circuit. 

For example, if we had a simple circuit of a battery and resistor, and needed to measure the voltage of the resistor, you would place the multimeter probes across the resistor as seen below.

Function #2 of a digital multimeter: Current 

Next of the three building blocks is Current.

Current can be defined by the flow of electrons within a conductive material. 

Knowing that the right current is flowing in a circuit is essential to protecting components from damage.Every component has a specific current requirement to operate effectively. 

If they are subject to currents above their maximum ratings for a given amount of time they can get damaged. 

Also, on the other hand, if you do not supply the right amount of current, the component will not work.

So, knowing that the right amount of current is being supplied is an essential function a digital multimeter needs to have. 

Unlike measuring voltage, current measurement needs to be done by placing the multimeter in series within a circuit.

Function #3 of a digital multimeter: Resistance 

The last piece of the fundamental building blocks of electricity is Resistance.

A digital multimeter has the ability to measure resistances of any type of material (specifically conductors). 

The main function of a digital multimeter resistance measurement is, well, to measure resistance of a component or circuit. 

But, resistance measurement yields more than just that, it can tell us the condition of a circuit or component as well (some components resistance deteriorates over time, while others increase. Both these are unwanted scenarios)

Resistance plays a big role in circuits, as it can control the amount of current flowing; the higher the resistance the lower the current, and the lower the resistance, the higher the current. 

Measuring the resistance is similar to voltage measurements and needs to be done across components or two points in a circuit. 

Function #4 of a digital multimeter: Continuity

Imagine you needed to drive to a certain destination. To get from Point A, to Point B, you are going to need a continuous path (in this case road).

If there happens to be a hole in the road, or a tree is obstructing it, you will not be able to get to your final destination.

The same holds true for current moving through wires, and components in a circuit. It is going to need a continuous path to flow freely. 

If a wire is cut in half, a component is not working, there is bad soldering, etc, this is going to prevent the flow of current.

Continuity is a function of a digital multimeter that lets you test the presence of a complete path between two points in a circuit. 

Function #5 of a digital multimeter: Temperature  

Digital multimeters now come with the added ability to measure Temperature.

Note, not all digital multimeters will be able to measure temperature. Multimeters that can measure temperature will come with a thermometer symbol on the dial. You can also check the manual of the multimeter. 

This is a great benefit because, if you are someone who needs to measure the basics (voltage, current, resistance), as well as need to take temperature measurements, you will not need a separate device to do so. 

You will have all the functions necessary in one convenient device.

The digital multimeter has the capability of providing temperatures in both Degrees Celsius and Degrees Farhanheit. 

Depending on the need of the application, there are multiple varieties of probes available for temperature measurement. 

Function #6 of a digital multimeter: Frequency

Frequency is a term used a lot in life. 

It defines the number of times an event occurs within a set period of time. 

For example, how many buses pass a bus station every hour. 

In the electrical world current is divided into Direct Current (DC) and Alternating Current (AC).

Alternating currents are represented by a Sine wave which involves currents that vary in magnitude and polarity. 

The frequency in the electrical world defines the number of times a sine wave of an alternating current repeats itself within a certain time period.

Circuits and electrical components are designed to operate at a certain fixed or variable frequency. If they are subject to different frequency values, the circuit will not operate as intended. 

So, digital multimeters have a Frequency function to ensure all values are correct. 

Function #7 of a digital multimeter: Capacitance 

Voltage, current, and resistance form the basic building blocks of electrical and electronic circuits. However, there are many other factors that play a part in the overall working. 

One of them is Capacitance.

Capacitance is defined as the capability of a component or device to store energy in the form of an electric field. 

Now, just like a resistor is created specifically for resistance, a component known as a capacitor has the specific purpose of providing a specific value of capacitance in a circuit. 

Digital multimeters can measure the capacitance of a capacitor (as well as other components). 

Function #8 of a digital multimeter: Diode test

Finally we have the Diode test.

A diode is a two terminal, semiconducting device that only allows current to flow in one direction. 

There are many different types of diodes which include; Light emitting diode, Zener, Shockley, PN junction, etc. 

Below are some of the uses of diodes in electrical circuits:

• Rectifying voltage: rectifying AC voltage to DC 
• Drawing signals from a supply
• Manipulating magnitude of a signal
• Mixing signals

The diode test function on a digital multimeter allows you to analyse a diode to ensure it is fully functional.

Here are some analysis of a diode after testing with a multimeter;

• A functional (forward-biased) diode should display a voltage ranging from 0.5 – 0.8 volts
• Multimeter will display infinite resistance (0L), when diode used as open switch
• A non-function diode will prevent flow from both directions. The multimeter will display infinite resistance (0L) for both directions

Uses of a digital multimeter

Now that we have gone through the different functions of the digital multimeter, let’s take a look at the uses of each function for particular applications. 

There are many uses for each particular function, but rather than going through them all, to save you time, I shall name the most common ones. 

Digital multimeter voltage function uses:

• Measure voltage drop across a component 
• Measure voltage drop between two points in a circuit
• Measure voltage of a car battery, or batteries used in electronic devices
• Measuring voltage of electrical components (AC)

Digital multimeter current function uses:

• Measure current through a circuit (series and parallel)
• Measure startup or in-rush current 
• Analyse power consumption of a circuit (how much current is being used by certain components)

Digital multimeter resistance function uses:

• Measure resistance of resistors
• Measure resistance of components, wires, overall circuit 
• Check resistance of components to see if the faulty 

Digital multimeter continuity function uses:

• Check if wire has continuous path
• Check for short circuits
• Check for open circuits 
• Check if component damaged

Digital multimeter temperature function uses:

• Measure temperature of transformer
• Installation of heat pump – ensure temperature is right
• Food – measure temperature of meats, liquids, etc (using different probes)
• Measure temperature of an enclosed electrical/electronic system

Digital multimeter frequency function uses:

• Measure frequency of circuit – ensure it is within the operating range
• Measure frequency of  AC motors 
• Measure frequency of oscillating circuits
• Audio – ensure right frequencies are used 

Digital multimeter capacitance function uses:

• Measure capacitance of capacitors
• Measure capacitance of wires, components, overall circuit

Digital multimeter diode function uses:

• Test functionality of diode
• Ensure diode is operating in right direction (forward bias)

Important factors of a digital multimeter

Now that we have covered the uses of digital multimeters, let’s take a look at some important factors to consider when choosing the right digital multimeter for the job. 

Just like if you were buying a new car, there are factors to consider like, does it have a radio, how big is the engine, is it electric, how well does it on long distance trips, does it have cup holders, etc.

Below are important characteristics of digital multimeters.

Note, these factors are not the same for all of them, but vary depending on the manufacturer.

Resolution

First on the list is Resolution, which is the smallest increment that the multimeter is able to detect and then display.

The smaller the value of increment results in the multimeter being able to display more numbers on its screen which leads to a higher resolution. 

For example, a resolution of 1mV (0.001V) is higher than 10mV (0.10V). 

Accuracy

You want your digital multimeter to be as accurate as possible. 

The less errors the better. 

Accuracy of a multimeter (which is presented as a percentage) defines the maximum error that is allowable within a certain criteria. 

This value compares the measurement value and the actual value of signal measured and specifies how close they are. 

For example, if a digital multimeter has an accuracy of + or  – 2%, and measures a voltage of 100V, the values can range from 98V – 102V. 

Range

The last and final factor is Range which is closely related to resolution.

Range is the maximum value that the multimeter can display. If the measurement is higher than the range of the multimeter, an overload scenario will occur displayed by ‘0L’. 

To obtain the most accurate readings, the lowest possible range should be used without overloading the multimeter. 

Below are some common ranges along with their resolutions;

You can see the relationship between range and resolution; the lower the range the greater the resolution, and the higher the range the lower the resolution.

Can a digital multimeter be used for AC and DC applications?

Yes, most digital multimeters can be used for DC and AC applications.

I say most because not all digital multimeters will have the ability to detect AC voltages and currents. It depends entirely on whether the manufacturer has created the multimeter to have those capabilities. 

Earlier, I briefly mentioned earlier that an alternating current is the main difference between AC and DC. 

Other than that, AC applications tend to deal with higher voltages than DC. So, a digital multimeter will need to be able to deal with those higher voltages.

Check the multimeters specification to see if it has the capability to measure AC currents and voltages.

Most of the time, it might only be able to measure AC voltages and not current

Also, the multimeter dial will include a voltage symbol with a curve underneath to show that it can read AC voltages.

DC voltages are depicted by a straight line. 

Advantages and disadvantages of a digital multimeter

There is a good and bad side to everything in life.The same is true for digital multimeters. It has its advantages as well as disadvantages. 

Advantages of a digital multimeter

• Easier to read (no parallax error with readings compared to analog multimeters)
• Higher accuracy
• Higher resolution 
• Have an ‘auto-polarity’ feature (in case you connect the multimeter probes the wrong way in a circuit)
• No moving parts (therefor last longer)
• No need for zero adjustment
• Size, cost, and power required have all reduced due to advancements in technology
• Have more functions
• Portable
• Some include onboard memory which can be used to store data for analysing later

Disadvantages of a digital multimeter

• The display requires power to operate and therefore consumes some of the power which could be used elsewhere.
• Can be subject to fluctuations or transients 
• Analog to Digital converter has limitations 
• Has a voltage limitation (if exceeded can damage the multimeter)

The post What is the use of a digital multimeter? appeared first on Electronic Guidebook.

They are development boards that include a microcontroller, power supply, inputs, outputs, Serial communication and much more.

You might have just purchased an Arduino, or are thinking about buying one to get stuck into the world of microcontrollers, electronics and programming. 

But, you might also be wondering whether you need a multimeter for an Arduino? While it is not necessary to have a multimeter when you start out with an Arduino, it is recommended that you do have one. Multimeters are great for troubleshooting problems that you might come across with your Arduino projects.

Also, Arduino development boards are not perfect. They are going to have some onboard problems sooner or later. 

Again, a multimeter is your best option at identifying the problem. 

What is an Arduino

Let’s take a deeper look at the Arduino. 

This will help you understand why you might require a multimeter. 

Below is one for the most common Arduino development boards; Arduino Uno.

As you can see the Arduino Uno has many components and parts that make up the development board which include;

• Power Input (barrel jack)
• 3.3V power input pin
• 5V power output pin
• Analog Input pins
• Digital Input/Output pins
• Reset Switch
• Microcontroller 
• USB port 

It is great for the beginner as you do not need to set up a microcontroller on a breadboard with a power supply and capacitors or resistors. 

It’s already all done for you on the development board. 

Inputs and outputs like LED’s, sensors, motors, displays can be connected to the digital pins as required. 

The Arduino can also be programmed using the USB port. It does not require complicated interfacing with a computer. 

What are the main uses of a multimeter

The multimeter is an electronic measuring instrument used on a daily basis by Electricians, Engineers, Hobbyists, DIYers and many others.

It has many functionalities but the main three are measuring Voltage, Current, and Resistance.

The most basic of multimeters should include these three measurements.

More complex multimeters can have more than just these three measurements which can include;

• AC (alternating current) voltage and amperage
• DC (direct current) voltage and amperage
• Resistance (ohms)
• Capacity (farads)
• Conductance (siemens)
• Decibels
• Duty cycle 
• Frequency (Hz)
• Inductance (henrys)
• Temperature Celsius or Fahrenheit 

Multimeters come in Analog and Digital versions, but analog multimeters are less common today due to their inaccuracy. 

The main use of a multimeter is to be able to diagnose and troubleshoot electrical and electronic circuitry. 

Finding faults and rectifying them is where the multimeter will be your best friend. 

Reasons why you might need a multimeter for an Arduino

When starting out on your journey with an Arduino, the projects you will be undertaking will be simple and troubleshooting will not necessarily require a multimeter. 

However, as you advance and the Arduino projects you embark on get more complex, you will no doubt require a multimeter to aid you in finding inevitable problems. 

We now know that a basic multimeter can measure the three basic electrical values which are voltage, current, and resistance. 

So let’s look at some reasons why you might want to invest in a multimeter to help with your Arduino.

Reason #1 why you might need a multimeter for Arduino: Testing Digital and Analog Pins

Ardnuinos come with a varying number of digital pins that can be used either as inputs or as outputs. 

Where inputs can include;

• Buttons
• Switches
• Sensors

And outputs can include;

• Motors
• Light Emitting Diodes (LED’s)
• Displays

Smaller components that require less current and voltage, can be powered by the 5 volts outputted at the digital pins.

However, if for some reason the digital pin does not seem to be powering whatever you have connected, you can use the voltage function of the multimeter to check what voltages are present at the digital pins.

Also, an Arduino will have designated analog pins where sensors can be connected to. 

A sensor will output voltages in analog form. 

However, arduinos only deal with digital data. 

The analog pins have the ability to convert the analog data to a digital form. 

Sometimes, the wrong digital values will be generated by software. 

You can see where the problem is by double checking the voltage at the analog pins and cross checking them with the digital values. 

Reason #2 why you might need a multimeter for Arduino: Testing Voltages

Initially your circuits will be confined to onboard the Arduino itself. 

But, sooner or later your projects will extend to outside of the Arduino, and onto something like a breadboard.

The more wiring and connections that are required, the more chances of error. These errors tend to show themselves as wrong voltages. 

Therefore fault finding when something is not working without a multimeter is going to be very very hard, and annoying.

Using a multimeter, the circuit schematic and a little electronic knowledge you should be able to find solutions to your problem in no time.

Reason #3 why you might need a multimeter for Arduino: Current consumption

If the next project you are undertaking requires a means of mobile power (like a battery), the circuit will need to be as efficient as possible to extend the life of the batteries. 

If you don’t know how much Current the system you are designing is consuming how will you know whether it is efficient or not?

Utilising the ability of the multimeter to measure current, you will be able to deduct if any improvements need to be made. 

Reason #4 why you might need a multimeter for Arduino: Resistance and Continuity

No matter whether you are a beginner or an expert, you are going to encounter a resistor or two, or a hundred.

These little buggers have many uses in an electronic circuit and come in a variety of shapes, sizes and resistance values. 

Even though resistors have colour bands on them which indicates what resistance value they are, it can get quite annoying trying to squint and constantly check the colours.

A workaround to this problem is using a multimeter (no surprises there)!

You will easily be able to tell what the resistance is of a resistor in any part of the circuit. 

Also, multimeter’s have another neat function which allows you to test Continuity.

This test allows you to see if two points of a conducting material are connected and therefore ‘continuous’ allowing the flow of current.

This is great for wires with insulation, or testing parts of a circuit that should be connected together. 

Can you get away with not having a multimeter initially?

When you initially start out with the Arduino, your projects are not going to be very complex. 

This might include projects such as reading button presses, blinking an LED, reading sensor values etc. 

The circuits involved with these are not too intense and only require a few connections. 

Saying this, you will still encounter problems. However, finding the cause of the problem and then the solution will be a bit easier. 

So, when starting out you do not need a multimeter.

But, it does not hurt to have one as part of your troubleshooting arsenal. 

Do you need an expensive multimeter for an Arduino?

No, you do not require an expensive multimeter.

When you are working with an Arduino, there are only a few measurements you want your multimeter to be capable of measuring; Voltage, Current, Resistance and Continuity. 

You can get multimeters that won’t break the bank which are still capable of performing these measurements so you can troubleshoot your Arduino and additional circuitry. 

The one thing you need to be aware of when selecting a multimeter is the ranges of voltages, and currents it can handle. 

It should be able to handle the voltage and currents of the Arduino and other circuitry. 

Final thoughts

So, you can see there are many reasons why you would want to invest in a multimeter when using an arduino.

It is a great tool for diagnosing and troubleshooting problems which are inevitable.

While you might not need a multimeter initially when starting out with an Arduino, it will prove useful as you progress in skill level and your projects get a bit more complex.

However, you do not need an expensive multimeter. A decent cheap one with the three basic measurement capabilities (voltage,current and resistance) should be just fine.

The post Do I need a multimeter for an Arduino? appeared first on Electronic Guidebook.

These quantities include things like current, voltage, resistance,capacitance, inductance and a whole list of others.

When designing a circuit, or testing a circuit for faults, you need to have a way of being able to measure these different quantities.  

Otherwise things could get messy real fast. 

An analog multimeter is an electronic and electrical measuring instrument that is used to measure a number of different electrical quantities.

The uses of an analog multimeter include;

• Measuring Voltage
• Measuring Current
• Measuring Resistance
• Transistor testing
• Diode testing
• Continuity test 

What is an analog multimeter

The Analog multimeter uses a needle that is placed on a numbered scale (that has a specified range), to display a number of different quantities as pictured in the image below. 

When the analog multimeter is used to measure these quantities, the needle is deflected depending on the force generated by the quantity being measured.

Inside the multimeter is a drum (which has a coil wound around it) between a pair of permanent magnets.

A magnetic field is induced, when a current passes through the coil. 

Since a magnetic field already exists due to the magnetic field, it reacts with the induced magnetic field causing a force which moves the needle. 

6 uses of an analog multimeter 

The analog multimeter has many different functions and uses, which make it a vital measuring instrument. 

Let’s take a look at the different uses of an analog multimeter. 

Use #1 of an analog multimeter: Measuring Voltage 

Voltage is one of the most important aspects of any electrical or electronic circuit.

It is the force that is generated by a power source (like a battery) that pushes electrons (current) around a closed circuit. 

In simple words voltage is electrical pressure.

Why is it important for an analog multimeter to measure voltage?

When an electrical or electronic circuit is built, it is created with components to work within a certain range of voltage values. 

This is because all components have minimum and maximum values within which they operate efficiently. 

Operating outside of these thresholds will cause the component to fail, which will also have a domino effect causing the rest of the circuit to fail.

So, having the ability to check that the right voltages are present between any two points in a circuit is needed. 

Also, if for some reason a component has stopped working, an analog multimeter can be used to check the voltage across it to see whether there is a Short or Open circuit.

Another great reason is checking the voltage of your power source. 

You might be powering your circuit with a power supply which is fine as it displays the voltage, but what if you are using batteries? How will you know if it is providing the right voltage to power your circuit.

Again that is where the analog multimeter’s voltage measuring function comes in handy.

Use #2 of an analog multimeter: Measuring Current

Those charged electrons that move around a circuit that receive the force from the voltage are also known as Current.

A more detailed description of Current would be the amount of charge that passes a given point in a circuit within a specific time period. 

The magnitude of the current is given in Amperes (A). 

Without getting into too much detail, the molecular structure of materials contains electrons. Depending on the material in question, the electrons can be held tightly or loosely. 

When the electrons move within a material it is known as current. How well and how many electrons move governs the substance’s ability to conduct electricity. 

Just like voltage, there are many reasons why it is essential to be able to measure current using an analog multimeter. 

One reason for measuring current is to see how much current a circuit or component consumes.

If you are designing a circuit that runs off a limited power source (like a battery), you want to be able to extend its lifetime as much as possible. 

While theory and calculation can give you an indication of how much current a circuit or component will consume, there are many factors that come into play in the real world.

You can use an analog multimeter to measure how much current is being consumed that will give a better indication than just theory alone.

The next reason is again along the same lines of measuring voltage. 

Like voltage ratings, electronic components have current ratings too. 

Exceeding these current ratings can cause irreversible damage. So having a way to measure how much current is being supplied to them using an analog multimeter is a necessity. 

Use #3 of an analog multimeter: Measuring Resistance

So, voltage is the force that pushes electrons, and current is the number of electrons that pass a given point.

Resistance is the ability of a material to resist current. 

Voltage, current and resistance are closely related, and make up the fundamentals of electricity. 

Their relationship can be summed by using Ohm’s law. 

Ohm’s law sums up the relationship between Voltage, Current and Resistance. The formula can be seen below. 

So the final piece of the puzzle is measuring resistance. 

If you want to decrease the current flowing in a circuit you will need to increase the resistance of the circuit and vice versa.

Everything in a circuit like a battery, wires, and electronic components have some sort of resistance which adds up to the overall resistance of the circuit. 

But, there are specific passive components known as Resistors that are created with a known resistance so you can increase or decrease the resistance of a circuit as desired.

Being able to measure the resistance using an analog multimeter lets you design a circuit as close to the desired resistance value as possible.

Since you cannot really know the resistance values of other components other than resistors, being able to measure their resistance is very helpful. 

While resistors have colour bands on them indicating their resistances, it can be time consuming trying to figure out what the value is. Sometimes it’s much easier to just use the analog multimeter to read the resistance. 

Use #4 of an analog multimeter: Continuity test

For a current to flow, it requires an unbroken path.

If that path is unbroken it will stop the flow of current within that circuit as can seen below.

Diagram A shows a circuit that has an unbroken path. Here current can flow without any interruptions.

The circuit in diagram B has a break in the circuit, therefore no current can flow. 

Circuits and components are connected together using wires of varying lengths, materials and diameters. 

However, these wires are shielded to protect us and other parts of the circuit. 

So, if you have a long thick wire that has a break somewhere in the middle, it is going to be very hard to know what the real issue is.

Analog multimeters have the ability to test the Continuity, which is the presence of a complete path that electrons can flow through. 

It not only can test the continuity of wires, but of switches, fuses, conductors and certain components. 

For example, you can test if a MOSFET is damaged or not not using the continuity test. 

When the leads of the multimeter are placed between the Source and Gate terminals of the MOSFET, there should be no continuity. 

An analog multimeter lets you know if there is continuity using an audible beeping sound.

Use #5 of an analog multimeter: Diode and Transistor  testing

Diodes are electronic components that can be found in almost every circuit.

Their most common applications include protection, rectification and switching. 

Unfortunately for the Diode, they tend to be the first to get damaged when a fault arises. So, having a way to test whether it has been damaged or not is essential.

Lucky for you and me, analog multimeters can test a diode to check it is functioning as it should be or whether it needs to be disposed of.  

The Light Emitting Diode (LED) is a type of diode which has the ability to emit light when forward biased. 

Just like a conventional diode, we can test a LED using an analog multimeter to see if it is working.

As well as the diode, the analog can be used to test the functionality of a Transistor. 

The Transistor is a semiconductor device used mainly to amplify or switch electronic signals and electrical power.

Testing a transistor using an analog multimeter follows a similar procedure to testing a diode. This is due to the fact that a bipolar transistor closely resembles back to back diodes.

Use #6 of an analog multimeter: hFE amplification test  

A hFE (Hybrid parameter forward current gain, common emitter) amplification is the  current gain of a transistor. 

This number represents the factor that the base current of the transistor is amplified to produce the output amplified current.

So, for example if a transistor had a base current of 1mA, and a hFE of 100, the output current at the collector of the transistor would be 100 mA.

Analog multimeters are equipped with a function that allows you to find out what a transistor’s hFE value is. 

Being able to test the hFE (gain) of a transistor comes in handy when you might have transistors lying around and aren’t too sure of hFE value. 

Applications of an analog multimeter

You can see the analog multimeter has many great uses and abilities. 

But, what applications are these functionalities commonly used for and who tend to use them?

Since the multimeter is a device that is primarily used with electricity, anyone who deals with electricity, would use the multimeter.

This can include;

• Electricians, 
• Electrical and Electronic Engineers
• Scientists
• Automotive Engineers
• Mechanics 
• Line installers and repairers

The main most common use for an analog multimeter is Fault Finding or Circuit Analysis.

As the name suggests, this involves finding faults in a circuit, wire, component etc, that is not working. 

There are many ways to approach fault finding, each with their own pros and cons depending on the circumstance.

Other than that, analog multimeters are also used in the design process of electrical and electronic systems to ensure components are functioning, as well as having the right values. 

Does an an analog multimeter have the same uses as a digital multimeter

The analog multimeter is less commonly used in the electrical and electronic field due to the rise of digital electronics. 

You can now use a Digital Multimeter (DMM) to perform the same tasks as its older counterpart.

However, they both have similar uses,  but each having its own pros and cons which I will discuss below. 

Difference between an analog and digital multimeter

When it comes to the multimeter, you have two options; Analog or Digital.

While both are used for the same purpose, they do have their differences.

So, before diving into what are the uses of an Analog multimeter, let’s quickly identify the main differences between an Analog and Digital multimeter.

Display – The first most obvious difference between an Analog and Digital multimeter is the display. The analog multimeter uses a needle to show the measured quantity, whereas the digital multimeter displays information in the form of digits. 

This is similar to the difference between an Analog and Digital clock.

Cost – The analog multimeter is less expensive compared to its digital counterpart due to the way that it is constructed and the components that it uses.

Accuracy – Since the analog multimeter uses a needle pointer to display values, this can increase the amount of parallax error when being read by the user giving it a lower accuracy.

Input Resistance – The input resistance of an Analog multimeter varies with range, while a digital multimeter stays constant for all ranges. 

The post 6 common uses of an analog multimeter appeared first on Electronic Guidebook.

Whether you are an experienced engineer, electrician, DIYer, electronic hobbyist etc, having a Multimeter is going to benefit you in many ways.

A multimeter is capable of more than one measurement which can include; Voltage, Current, Resistance and others depending on the complexity of the multimeter.

Of the many measurements, Voltage is one of the most common parameters it is used to measure.

But, the multimeter is not a perfect measuring instrument. 

Sometimes it might read the wrong voltage. 

You might be reading this because your multimeter is reading the wrong voltage. 

So, does that mean you need to dispose of your multimeter and get a new one?

Of course not! 

Below are some possible reasons why a multimeter is reading the wrong voltage:

• Low battery
• Faulty Leads
• Incorrect placement of probes
• Component failure
• Fuse blown 

For a more detailed description for each reason, read on. 

Note, make sure to always first try the standard procedure of turning your multimeter off and on and then checking to see if the wrong voltage is still being read. 

5 reasons why a multimeter is reading wrong voltage

Let’s take a look at each of the reasons why a multimeter is reading the wrong voltage in more detail.

Reason #1 a multimeter is reading the wrong voltage: Low battery

The first and most possible reason why your multimeter is reading the wrong voltage is because its battery has decreased below its nominal voltage. 

Electronic components, devices all work within a specific voltage range. 

Whether it be your mobile phone, calculator, toaster, Television and so on.

However, some of these devices have the luxury of being plugged into a wall outlet and being powered ‘infinitely’ (or until you stop paying your bills).

Other devices which are mobile in nature run of a limited power source such as a battery. 

A multimeter is a device that is mobile because it needs to be carried and used in different locations. 

Therefore it needs to be powered by batteries. 

This can cause issues with reading voltages when the batteries start to drop in power. 

A drop in battery voltage can cause the internal reference voltage to drop which then could cause the meter reading to be high.

So, if you are not getting normal voltage readings on your multimeter, replace the current batteries with newer ones and then check again. 

If you get normal readings, you know the old batteries have dropped past their nominal voltage. 

Even if you haven’t used your multimeter in a long time, the batteries could still potentially drop in voltage. 

So beware of that.

Reason #2 a multimeter is reading the wrong voltage: Faulty Leads

If you replaced the batteries with newer ones, and you are still getting the wrong voltage readings, then the next possible issue you could have is faulty leads.

To test your multimeter leads, set the multimeter to read resistance and then touch the probes together.

The resistance that should be displayed for multimeter leads that are functioning properly should be zero.

If for some reason the resistance reading is above one, or all over the place, your multimeter leads are faulty and could be the reason your multimeter is reading the wrong voltage. 

Try replacing the leads to see if that rectifies the issue.

Another issue could be that the probes are not connected properly to the multimeter. 

If there isn’t a proper connection, there won’t be a proper electrical conduction and therefore the wrong voltage will be displayed. 

So, make sure your multimeter probes are connected properly. 

Reason #3 a multimeter is reading the wrong voltage: User error

Ok, this reason comes down to user error.

User error involves the user (the person using the multimeter) not placing the multimeter leads on the right points of a circuit or battery. 

This might seem like a silly reason as to why a multimeter is reading the wrong voltage, but it is entirely possible and has happened to me plenty of times.

This could be caused by not reading the schematic right, or, placing it in the wrong place by mistake. 

Either way, double check that you are measuring the right parts of the circuit if your multimeter is reading the wrong voltage. 

Reason #4 a multimeter is reading the wrong voltage: Fuse blown

Fuses are used in the electrical and electronic field as a way of providing safety to currents that exceed the normal threshold of a device. 

This threshold can be different for different devices so there are fuses that can handle different levels of current.

When that current threshold is exceeded, the metal wire inside the fuse melts, disrupting the flow of current. 

Multimeters have a maximum current that they can handle.

So, to protect them and you from overcurrents, they are fitted with fuses. 

If you happen to use the multimeter to measure the current or voltage outside its maximum threshold, the fuse is going to break.

If the fuse is blown, your multimeter is not going to function properly and therefore display incorrect voltage values. 

If you want to know how to check if your fuse is blown and how to replace it watch the video below.

Reason #5 a multimeter is reading the wrong voltage: Component failure

The last possible reason why your multimeter could be reading the wrong voltage might not be an issue with the multimeter itself.

The issue could be with the electronic/electrical component that you are testing.

Electronic components are not perfect. They too are subject to failure. 

Below are a couple ways electronic components could fail;

• Exceeding the current or voltage rating of the component
• Electrostatic Static Discharge

If a particular component has failed, this could cause a wrong voltage reading on the multimeter when testing another part of the circuit (depending on the circuit itself of course). 

How to be certain your multimeter isn’t reading the wrong voltage

So, the multimeter displays a voltage that you are not expecting.

You might know what voltage it should be displaying, but how can you be certain that something is wrong with the multimeter?

If you have a power supply, set it to a voltage (that is within the range of the multimeter) and then use the multimeter to test the output voltage. 

If the voltage on the multimeter matches the power supply’s voltage, great! 

However, if the voltages do not match, you know you have a problem.

You might not have a power supply lying around though.

That’s fine.

Get yourself a new battery (AA, AAA, D-cell, 9V etc), and test the voltage. Since it is a new battery, the voltage when testing should be around the full capacity value of the battery. 

Again, if the multimeter is displaying the wrong voltage, you know you have a problem and can cycle through the 5 possible reasons to find the problem. 

How to avoid reading the wrong voltage with a multimeter

It can be quite a waste of time having to go through all the steps of figuring out why your multimeter is reading the wrong voltage. 

You might know the saying, “Prevention is the best cure”.

This is having habits or procedures in place that prevent a problem from arising in the first place.

Below are some things you can do to avoid the situation of your multimeter reading the wrong voltage for each of the 5 possible reasons mentioned earlier. 

Low battery

You cannot really control how your battery performs. 

But, you can control the quality of the batteries you buy for your multimeter. 

Invest in good quality batteries that will last longer. This will save you from always having to change the batteries of the multimeter (which will save you time and money).

Faulty Leads

Depending on how often you use the multimeter, and the way you use them, you will be twisting, turning, stretching them in every direction. 

This is going to cause some wear and tear on the multimeter leads which will no doubt cause them to fail in time.

So, to ensure longevity, make sure to handle the leads with care when using the multimeter.

User Error

Mistakes are going to be made.

We are human after all.

But, we can reduce the frequency at which we make errors when reading voltages on the multimeter with a few things we do before testing.

Never assume anything. Always make it a habit to read the schematic of the circuit you are reading to identify the right points where to place the multimeter leads.

Test more than once to see if you are reading the same voltage. 

You might have got it wrong the first time, so testing more than once will eliminate any doubt. 

Also, make sure you are making a proper connection with whatever you may be testing. 

Fuse blown

To avoid blowing the fuse of your multimeter, get to know your multimeter.

All multimeters have different maximum current and voltage ratings.

Read your multimeter’s manual, and familiarise yourself with its maximum voltage and current ratings. 

This will prevent you from testing any currents and voltages outside of the limits of your multimeter.

Component failure

Similarly with the multimeter, make sure to stay within the voltage and current limits of the components in your circuit.

Electronic components are also susceptible to damage via electrostatic discharge when you are handling them.

To prevent this follow the points below

• Keep electronics away from blowing air
• Keep electronics away from plastics and synthetic materials 
• Invest in an ESD mat (which is designed to drain static discharge away from you)

The post 5 reasons your multimeter is reading the wrong voltage appeared first on Electronic Guidebook.

Multimeter leads are an essential part of the multimeter when it comes to testing.

But, what are multimeter leads made of? Multimeter leads are made of a combination of wires, plugs, probes and insulation. In order to be able to measure current, voltage and resistance, the multimeter leads need to be made of conducting material that allows current to pass through. The material that is chosen for the wire is Copper, as it is a great conductor. Also, the wires are covered with an insulation material to protect you from the currents. 

The ends of the leads can either be probes, alligator clips or banana plugs. These also need to be made of conducting material that can carry current. 

Purpose of multimeter test leads

Problems are part of everyday life. There is no way of avoiding them. But, fortunately there are tools that we have developed to help us overcome these problems.

Electrical and Electronic applications are no different. Things rarely go as planned and you are inevitably going to come across problems and setbacks with your projects.

The multimeter is a troubleshooting instrument that was created to help identify problems in electrical and electronic systems. 

The most basic multimeters are capable of measuring voltage, current and resistance. This is enough to help you identify many problems an electronic or electrical system could have. 

An essential component of a multimeter are its leads. 

Just like our hands are an essential part of our body, which let us feel and control the external world, multimeter leads are an important part of a multimeter that enable it to ‘feel’ and attach to circuitry for testing.

Sections of what multimeter leads are made of 

Multimeter leads can be broken up into four sections; The Plug, Cable, Probe and Insulation.

The Plug

If we did not have a way to connect to a multimeter, it would be rendered useless. The multimeter has terminals which test leads can interface to.

Multimeter leads have a plug at the end (known as a banana plug) which is connected to one of the multimeter terminals. 

Cable

The cable is the part of the multimeter that bridges the gap between the plug and the probe. The cable can vary in length.

It lets you maneuver and position the probe as needed. 

It would be quite annoying if you had to constantly carry the multimeter with you to each part of the circuit everytime you needed to test. 

The cable (that varies in length) allows you to keep the multimeter in a stationary position while you can test different parts of a circuit. 

Probe

I mentioned earlier that multimeter leads are like our hands. In that case the multimeter lead, the probe would be the fingers.

The probe is the part of the multimeter lead that makes contact with components, wires and different parts of a circuit.

There are many different types of probes available for different applications. I will cover these later.

Insulation

The final section of a multimeter lead is the insulation.

Insulation is vital in electrical and electronic wires, as it protects you from currents and voltages. The insulation of multimeter leads is there for the same reason.

It covers all of the cable, and plug, and parts of the probe. 

The most common insulating material used is silicone. 

What are the different parts of the multimeter leads made of?

While the materials used for each part of the multimeter lead varies, they need to be constructed with materials that are capable of conducting electricity.

Metals are the best conductors of electricity and therefore are the go to when designing multimeter leads. 

As well as the ability to conduct electricity, multimeter leads need to be able withstand high currents, voltages and temperatures. 

The most common metal used for the cable is Copper, as it is a great conductor of electricity. One thing that needs to be taken into consideration when choosing a material for the cable is the resistance of the cable as it should not affect the current and voltages being tested. 

A standard cable used for multimeter leads should not exceed 30 Mega Ohms. 

The plug and probe consists of a metal plug/pin that is covered by insulation. 

Different types of multimeter test lead extension

While the plug, and cable of a multimeter lead are standard and rarely vary, there are many different types of probes available.

Depending on what you are testing, rest assured there will be a probe available to make testing an easier process. 

Apart from the standard probe, the ends of multimeter leads can be Alligator clips,  and Banana Plugs among the most common of multimeter lead extensions. 

Multimeter lead extensions #1 : Standard Probe

The first and most common extension for multimeter lead is the standard probe as pictured below.

This type of probe is great for testing components of circuits on Printed Circuit Boards (PCB’s), or breadboards. 

It is also great for testing Surface Mount Devices (SMD’s) which are harder to test with other multimeter lead extensions. 

The long needle of the probe allows you to test hard to get places. 

Multimeter lead extensions #2: Alligator Clips

Next on the list of multimeter lead extensions are Alligator Clips.

Testing wires or a component’s leads while holding probes can be quite cumbersome.

Alligator clips are perfect as they allow you to grab wires and leads of components making a secure connection.

This comes in handy when you need to connect the multimeter leads and do something else while testing. The alligator clips and remain to whatever you attached them to while you do whatever else you need to do.

Multimeter lead extensions #3: Banana Plugs

Number 3 of the list of common multimeter lead extensions are banana plugs. 

Some of the time you will need to test a circuit that isn’t exposed (you cannot see the circuit board, or get to it using probes or alligator clips).

Sometimes they will include a jack (or socket) as pictured below. 

To be able to test a circuit with this configuration, you will need to use banana plugs. 

Are all multimeter leads made the same?

Electrical and electronic applications vary in voltages and current. Electrical voltages can reach values up to 1000 volts, while electronic voltages can be as low as 1.2 volts.

So, due to this, multimeters are designed specifically to withstand voltages and currents they will be used in.

Multimeters are designed by manufacturer’s to comply with NFPA 70E category requirements (CAT ratings).

These ratings are location based, and determine which type of multimeter is suitable for the job.

Similarly, multimeter leads have to abide by these ratings. 

So, multimeter leads will be designed accordingly for the application they will be used in, and given a CAT rating.

What application are multimeter leads used for?

As we saw above, the CAT rating of a multimeter will determine where it will be suitable to use.

Below is a table of different CAT ratings, and their applications of where they should be used.

What is the best wire for multimeter test leads

While there isn’t a specific type of wire that is best for multimeter leads, choosing the right kind of cable that is suited for the application should be taken into consideration.

As you saw above, CAT ratings help you choose the right multimeter and test leads for the job at hand. Depending on what type of voltages and currents you are dealing with, you can choose the right multimeter lead.

The multimeter should be able to handle the voltages, currents and temperatures of the circuitry it is testing. 

Are positive and negative multimeter leads made of the same material?

Testing electrical and electronic systems with a multimeter requires two multimeter leads. A Positive and Negative lead.

Since the voltages and currents will not vary across either of these multimeter leads, they are both made of the same material. 

How to properly use multimeter leads

Using a multimeter and its leads can be a bit confusing when learning how to use them. But, with the right knowledge and practice, you will be able to troubleshoot circuits with no problem.

If you are just starting out, check out the video below on how to properly use a multimeter and its leads.

Can you make your own multimeter test leads?

Maybe you have misplaced your last set of multimeter leads and need to do some testing urgently. Is it possible to make your own multimeter test leads?

Yes! Below is a video on how to make your very own multimeter leads. 

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