Electronic Components Testing (Step by Step Guide, 2023)
Electronic components testing is a process to know if the components are working fine or not in the circuit or off the circuit.
The steps of the testing process vary from component to component.
But in my experience, these steps are easy to follow and remember. And you will become good at testing electronic components with time.
Practice is the key.
To successfully conduct a testing process, we need to have basic electronics test equipment in our lab. This is mandatory.
Some basic testing pieces of equipment are the multimeter, ESR meter, Oscilloscope, capacitance meter, Ohm meter, and much more.
Now, there are so many electronic components out there. That is why this article will be a long guide that will walk you through the testing process of each component step by step.
If the above introduction has got your attention, and you are an electronics beginner or hobbyist. Then I am sure you will like the rest of the article as well.
At the end of this article you should be able to:
Know the general process and theory of testing various electronic components
Tell if a resistor, capacitor, inductor, transistor, diode, LED, and IC is good or bad
Use a multimeter for testing effectively
Learn how to use a proper component tester and ESR meter
Use IC tester for integrated circuit testing
and so much more
Sounds interesting? Then, let’s get started.
Electronic Components Testing Theory
Before getting into any specific electronic component testing process. It is important that we understand the testing process in general.
This general process will help us in the long run. As it will make us prepare for unseen or uncertain situations throughout our career and working with electronics.
I believe the first step is to identify the nature of the component
1. Component nature
What do I mean by this?
Basically, there are two types of electronic components. One group is called the Active Components while the other is called the Passive Components.
Active components are those that need external power for their operations. They provide some type of gain to the circuit. Example are:
Transistors
Operational amplifiers (Op-Amps)
Integrated Circuits (ICs)
MOSFETs
JFETs
IGBTs
SCRs
While on the other side, there are passive components. They don’t need any external power for their proper operations. And don’t provide gain, in fact, they dissipate power. Examples are:
Resistors
Capacitors
Inductors
Switches
Connecting lines
Diodes
Transformers
Relays
Categorizing the components this way is the key to accurate testing results. So as a beginner, first know what type of component you are dealing with.
2. Component technology
Now, besides active and passive. There are two very important technologies used for the making of electronic components.
They are:
Through holes components
Surface mount devices (SMDs)
Through hole components are those which have thick terminals you may say legs that go through the holes of PCBs.
While on the other hand, SMDs are soldered on the surface of the PCBs. Both components have their own uses and advantages.
It is not like which is better – it totally depends on what you are designing. Through holes are mostly used for handling high power while SMDs are preferred when we want a compact size product.
The technology type doesn’t really change the testing process for the same component.
For example, no matter if you are testing the SMD resistor or a through hole resistor. The testing steps and process remain the same. Yes, a slight change will occur in the equipment probes and sometime you will need a whole new test equipment.
3. General methods for electronic components testing
Alright!
So, you now know that first, you will identify the component nature and then the technology. After that, you will apply the following methods.
First, let me discuss these methods in general. Then in the below sections, we will adjust these methods according to each specific component.
a. The Visual Inspection method
As you can guess from the name, it is the method of generally seeing a component with our eyes.
In this method, we inspect the component, both in circuit or off circuit, and see for the following obvious scenarios:
If it busted open
There is any leakage
If it is broken,
If there are any visible crakes
If the color has changed
If there are some burning symptoms on the PCB near the component
If there is any naughty smell
Upon turning the circuit there are some strange sounds coming from the component
Also, the inner guts that you feel inside your heart about the component
If there are any of the above situations, then it is time to directly replace that component if it is inside a circuit board. Or don’t even think to use that component if it is off the circuit.
b. Using the test equipment
Most of the time a component will be detected from simple visual inspection. But it is not true for all cases. Then test equipment is the way to go with.
By the way, test equipment alone can’t help you if you don’t have the right knowledge about the circuits. So, I am assuming you already know exactly which component you want to test.
Alright!
In general, every testing of a component using any testing equipment goes like this:
You take your component and the required test equipment
For example, for resistor testing: you take the resistor and the multimeter
You connect the component to the equipment in the required way
You take the reading on the screen of your device
Using the knowledge you then compare the reading with the exact reading (you already know or given by the manufacturer)
If the reading matches the exact reading, you have a good component, else it is a bad component
Electronics is a huge discipline. Its subfields range from circuits theory to advanced applied electromagnetic. For these reasons you have to have the required testing equipment which totally depends on what subfield you work in.
4. Right Test Equipments
I am writing this article for beginner people. People in this group fall into low frequency circuits. Which means we will only need the following tools.
Digital Multimeter
Component tester
LCR Meter and tweezers (SMD component testing)
IC tester
Oscilloscope and a function generator (for advanced testing, totally optional for beginners)
Just for extra knowledge. If your components are high frequency then you should have a working spectrum analyzer and vector network analyzer (VNA) as well for the measurement of S-parameters and reflection coefficients.
a. Digital multimeter
When it comes to electronic components testing, a digital multimeter is the must have device. I believe without this tool you will have a hard time testing the components.
Now, what is a digital multimeter?
It is an electronic measuring device that can measure the following quantities with high accuracy:
Resistance of resistor (both through hole and SMD resistor)
Voltage and current measurements for both AC and DC
Continuity testing
Capacitance measurements
We will use this device a lot in this post.
b. Component tester
A multimeter is good, but it requires you to have enough testing knowledge about each component. For example, for a resistor, you must be able to tell which reading on the multimeter means it is a good resistor. And which reading means the resistor is bad?
And the same goes for every component.
To tackle this we need to have another tool, called the component tester. It directly tells us which component is good and which is bad.
This doesn’t mean this device will eliminate the need for a multimeter. No, because it is not best for measuring voltages, current, and in circuit component testing.
Each device has its own pros and cons, it totally depends on the situation.
c. LCR meter or tweezers
Multimeter and component tester can help you. But when it comes to onboard component testing, you are in need of an LCR meter (best for through holes) and an LCR tweezer (best for SMDs).
Well, if you have LCR meter then just by using tweezer probes you can test the SMDs with the same meter. But it is good to have a dedicated tool for SMDs as it is very convenient to use.
d. Integrated circuits (ICs) tester
You know, a circuit has capacitors, inductors, resistors, connecting wires, relays, transformers, diodes, transistors, and connectors. For all these the above devices are enough.
But there is a single piece missing, and that is integrated circuits. Integrated circuits (ICs) are almost everywhere in electronics. I am sure you have seen them plenty of times. They look like black small boxes in electronic circuits.
How to test those?
Well, you can use a multimeter for testing ICs as well. But this is not very efficient. For this, we should have a dedicated IC tester.
IC itself is a discrete circuit with its own functions and feature. We use ICs in circuits to reduce the circuit space and improve efficiency.
Alright!
We are done with basic equipment that I believe is a must for a beginner. Now let’s get into how to use these tools to test various electronic components.
1. Resistor testing
A resistor is the most used electronic component. It is a two terminals device with the ability to resist the flow of current through it.
Above is the circuit symbol and some real-time resistors. One thing to remember about resistors is, that they are passive components.
We use a resistor to protect a circuit or a portion of a circuit from overcurrent flow. It is like a safety device against large unwanted currents.
Now, there are many types of resistors out there but all types serve the same function, i.e. to resist the current flow.
Let’s see how we can test this electronic component to see if it is good or bad. You must always test a resistor before putting it in any circuit.
The reason is if it’s a bad one, especially a short one then there is a chance you can damage your circuit due to over-current flow.
Method 1: Visual Inspection
In this method, we look for some obvious signs that help us to identify any bad resistor individually or inside the circuit board.
Following are the few signs you should look for:
The body of the resistor may be blown
The resistor may be busted open
There is a crack in the body
If the resistor is on PCB and the PCB color has changed to black around the body or terminal of the resistor.
There is a change in the color of the resistor
I think we need to look at some examples of bad resistors so that you can exactly know what I am actually talking about here.
You can clearly see the differences.
Now, in general, you can spot a bad resistor by visual inspection in no time. There might be cases where you will not be able to find the above signs useful.
Then you have to use your own judgment. But I am pretty sure a bad resistor will show itself to you if you pay a little attention.
Method 2: Using a multimeter
So, the resistor has no obvious signs. Then we can use a multimeter to find out if it is good or bad. Let’s say we have a 1K resistor under the test. We know this value from the color code of the resistor.
Follow the following steps for this method:
Take your multimeter, below is my KM601 (Product link), and set it to the resistor function
Take your resistor and connect it to the probes of your multimeter
Note the reading carefully
Read the color code of your given resistor.
Compare the color code value with the actual reading of the multimeter.
If these values match with the given resistance tolerance range, you have a good resistor, else your resistor is bad.
You can not use it for in-circuit resistor testing. Because in circuits resistors are connected with other electronic components as well.
If you try to measure resistance that way, chances are you will get an equivalent component’s resistance rather than the specific resistor value. This may lead to the bad judgment of a resistor.
For an in-circuit resistor, first, desolder the resistor from the circuit, test it, and then resolder it back if it is a good one.
Types of bad resistors: Basically, there are two types of bad resistors:
Open resistor
Short resistor
Open resistor shows “OL” on the multimeter screen. While a short resistor shows “0” zero resistance on the multimeter.
So, for in-circuit resistor testing, we are interested in these two types. We follow the same steps as above and see the results if it is an open or short resistor. If not then the value of a good resistor is in the proximity of the actual value (depending on which type of other circuit elements are there near to it).
For example, a good 1K resistor should give you a value of around 850 to 999 Ohm. Please don’t forget to turn off your circuit (take off the battery) before using the multimeter or measuring any value.
The same process applies to SMD resistors as well.
Method 3: Using a component tester
Now, this last method is very interesting. Exciting in the sense it is a new way of testing electronic components. To perform this method I am using my M328 component tester (Product link).
Follow the following steps to perform this method:
Turn on the component tester.
Put the resistor (1K that I used above) you want to test in the socket of your tester.
Press the test button.
See the results on the screen.
If the resistor is good it will show you its value. If it is bad, it will tell you that the resistor is bad – it is that simple.
The limitation of this method is you can not use it for in-circuit resistance testing.
Other than that it is a very easy and straightforward method to apply. It will save you a lot of time and resources.
2. Capacitor testing
A capacitor is another fundamental level component. It has two terminals and acts as a passive energy-storing device.
It has two types. The electrolytic and the ceramic type.
The electrolytic type capacitors are polarity dependent meaning that they have positive and negative terminals.
While ceramic capacitors are independent of polarity. You can connect them in the circuit without worrying about their positive or negative terminals.
Electronic Components Testing (Step by Step Guide, 2023)
Electronic components testing is a process to know if the components are working fine or not in the circuit or off the circuit.
The steps of the testing process vary from component to component.
But in my experience, these steps are easy to follow and remember. And you will become good at testing electronic components with time.
Practice is the key.
To successfully conduct a testing process, we need to have basic electronics test equipment in our lab. This is mandatory.
Some basic testing pieces of equipment are the multimeter, ESR meter, Oscilloscope, capacitance meter, Ohm meter, and much more.
Now, there are so many electronic components out there. That is why this article will be a long guide that will walk you through the testing process of each component step by step.
If the above introduction has got your attention, and you are an electronics beginner or hobbyist. Then I am sure you will like the rest of the article as well.
At the end of this article you should be able to:
Know the general process and theory of testing various electronic components
Tell if a resistor, capacitor, inductor, transistor, diode, LED, and IC is good or bad
Use a multimeter for testing effectively
Learn how to use a proper component tester and ESR meter
Use IC tester for integrated circuit testing
and so much more
Sounds interesting? Then, let’s get started.
Electronic Components Testing Theory
Before getting into any specific electronic component testing process. It is important that we understand the testing process in general.
This general process will help us in the long run. As it will make us prepare for unseen or uncertain situations throughout our career and working with electronics.
I believe the first step is to identify the nature of the component
1. Component nature
What do I mean by this?
Basically, there are two types of electronic components. One group is called the Active Components while the other is called the Passive Components.
Active components are those that need external power for their operations. They provide some type of gain to the circuit. Example are:
Transistors
Operational amplifiers (Op-Amps)
Integrated Circuits (ICs)
MOSFETs
JFETs
IGBTs
SCRs
While on the other side, there are passive components. They don’t need any external power for their proper operations. And don’t provide gain, in fact, they dissipate power. Examples are:
Resistors
Capacitors
Inductors
Switches
Connecting lines
Diodes
Transformers
Relays
Categorizing the components this way is the key to accurate testing results. So as a beginner, first know what type of component you are dealing with.
2. Component technology
Now, besides active and passive. There are two very important technologies used for the making of electronic components.
They are:
Through holes components
Surface mount devices (SMDs)
Through hole components are those which have thick terminals you may say legs that go through the holes of PCBs.
While on the other hand, SMDs are soldered on the surface of the PCBs. Both components have their own uses and advantages.
It is not like which is better – it totally depends on what you are designing. Through holes are mostly used for handling high power while SMDs are preferred when we want a compact size product.
The technology type doesn’t really change the testing process for the same component.
For example, no matter if you are testing the SMD resistor or a through hole resistor. The testing steps and process remain the same. Yes, a slight change will occur in the equipment probes and sometime you will need a whole new test equipment.
3. General methods for electronic components testing
Alright!
So, you now know that first, you will identify the component nature and then the technology. After that, you will apply the following methods.
First, let me discuss these methods in general. Then in the below sections, we will adjust these methods according to each specific component.
a. The Visual Inspection method
As you can guess from the name, it is the method of generally seeing a component with our eyes.
In this method, we inspect the component, both in circuit or off circuit, and see for the following obvious scenarios:
If it busted open
There is any leakage
If it is broken,
If there are any visible crakes
If the color has changed
If there are some burning symptoms on the PCB near the component
If there is any naughty smell
Upon turning the circuit there are some strange sounds coming from the component
Also, the inner guts that you feel inside your heart about the component
If there are any of the above situations, then it is time to directly replace that component if it is inside a circuit board. Or don’t even think to use that component if it is off the circuit.
b. Using the test equipment
Most of the time a component will be detected from simple visual inspection. But it is not true for all cases. Then test equipment is the way to go with.
By the way, test equipment alone can’t help you if you don’t have the right knowledge about the circuits. So, I am assuming you already know exactly which component you want to test.
Alright!
In general, every testing of a component using any testing equipment goes like this:
You take your component and the required test equipment
For example, for resistor testing: you take the resistor and the multimeter
You connect the component to the equipment in the required way
You take the reading on the screen of your device
Using the knowledge you then compare the reading with the exact reading (you already know or given by the manufacturer)
If the reading matches the exact reading, you have a good component, else it is a bad component
Electronics is a huge discipline. Its subfields range from circuits theory to advanced applied electromagnetic. For these reasons you have to have the required testing equipment which totally depends on what subfield you work in.
4. Right Test Equipments
I am writing this article for beginner people. People in this group fall into low frequency circuits. Which means we will only need the following tools.
Digital Multimeter
Component tester
LCR Meter and tweezers (SMD component testing)
IC tester
Oscilloscope and a function generator (for advanced testing, totally optional for beginners)
Just for extra knowledge. If your components are high frequency then you should have a working spectrum analyzer and vector network analyzer (VNA) as well for the measurement of S-parameters and reflection coefficients.
a. Digital multimeter
When it comes to electronic components testing, a digital multimeter is the must have device. I believe without this tool you will have a hard time testing the components.
Now, what is a digital multimeter?
It is an electronic measuring device that can measure the following quantities with high accuracy:
Resistance of resistor (both through hole and SMD resistor)
Voltage and current measurements for both AC and DC
Continuity testing
Capacitance measurements
We will use this device a lot in this post.
b. Component tester
A multimeter is good, but it requires you to have enough testing knowledge about each component. For example, for a resistor, you must be able to tell which reading on the multimeter means it is a good resistor. And which reading means the resistor is bad?
And the same goes for every component.
To tackle this we need to have another tool, called the component tester. It directly tells us which component is good and which is bad.
This doesn’t mean this device will eliminate the need for a multimeter. No, because it is not best for measuring voltages, current, and in circuit component testing.
Each device has its own pros and cons, it totally depends on the situation.
c. LCR meter or tweezers
Multimeter and component tester can help you. But when it comes to onboard component testing, you are in need of an LCR meter (best for through holes) and an LCR tweezer (best for SMDs).
Well, if you have LCR meter then just by using tweezer probes you can test the SMDs with the same meter. But it is good to have a dedicated tool for SMDs as it is very convenient to use.
d. Integrated circuits (ICs) tester
You know, a circuit has capacitors, inductors, resistors, connecting wires, relays, transformers, diodes, transistors, and connectors. For all these the above devices are enough.
But there is a single piece missing, and that is integrated circuits. Integrated circuits (ICs) are almost everywhere in electronics. I am sure you have seen them plenty of times. They look like black small boxes in electronic circuits.
How to test those?
Well, you can use a multimeter for testing ICs as well. But this is not very efficient. For this, we should have a dedicated IC tester.
IC itself is a discrete circuit with its own functions and feature. We use ICs in circuits to reduce the circuit space and improve efficiency.
Alright!
We are done with basic equipment that I believe is a must for a beginner. Now let’s get into how to use these tools to test various electronic components.
1. Resistor testing
A resistor is the most used electronic component. It is a two terminals device with the ability to resist the flow of current through it.
Above is the circuit symbol and some real-time resistors. One thing to remember about resistors is, that they are passive components.
We use a resistor to protect a circuit or a portion of a circuit from overcurrent flow. It is like a safety device against large unwanted currents.
Now, there are many types of resistors out there but all types serve the same function, i.e. to resist the current flow.
Let’s see how we can test this electronic component to see if it is good or bad. You must always test a resistor before putting it in any circuit.
The reason is if it’s a bad one, especially a short one then there is a chance you can damage your circuit due to over-current flow.
Method 1: Visual Inspection
In this method, we look for some obvious signs that help us to identify any bad resistor individually or inside the circuit board.
Following are the few signs you should look for:
The body of the resistor may be blown
The resistor may be busted open
There is a crack in the body
If the resistor is on PCB and the PCB color has changed to black around the body or terminal of the resistor.
There is a change in the color of the resistor
I think we need to look at some examples of bad resistors so that you can exactly know what I am actually talking about here.
You can clearly see the differences.
Now, in general, you can spot a bad resistor by visual inspection in no time. There might be cases where you will not be able to find the above signs useful.
Then you have to use your own judgment. But I am pretty sure a bad resistor will show itself to you if you pay a little attention.
Method 2: Using a multimeter
So, the resistor has no obvious signs. Then we can use a multimeter to find out if it is good or bad. Let’s say we have a 1K resistor under the test. We know this value from the color code of the resistor.
Follow the following steps for this method:
Take your multimeter, below is my KM601 (Product link), and set it to the resistor function
Take your resistor and connect it to the probes of your multimeter
Note the reading carefully
Read the color code of your given resistor.
Compare the color code value with the actual reading of the multimeter.
If these values match with the given resistance tolerance range, you have a good resistor, else your resistor is bad.
You can not use it for in-circuit resistor testing. Because in circuits resistors are connected with other electronic components as well.
If you try to measure resistance that way, chances are you will get an equivalent component’s resistance rather than the specific resistor value. This may lead to the bad judgment of a resistor.
For an in-circuit resistor, first, desolder the resistor from the circuit, test it, and then resolder it back if it is a good one.
Types of bad resistors: Basically, there are two types of bad resistors:
Open resistor
Short resistor
Open resistor shows “OL” on the multimeter screen. While a short resistor shows “0” zero resistance on the multimeter.
So, for in-circuit resistor testing, we are interested in these two types. We follow the same steps as above and see the results if it is an open or short resistor. If not then the value of a good resistor is in the proximity of the actual value (depending on which type of other circuit elements are there near to it).
For example, a good 1K resistor should give you a value of around 850 to 999 Ohm. Please don’t forget to turn off your circuit (take off the battery) before using the multimeter or measuring any value.
The same process applies to SMD resistors as well.
Method 3: Using a component tester
Now, this last method is very interesting. Exciting in the sense it is a new way of testing electronic components. To perform this method I am using my M328 component tester (Product link).
Follow the following steps to perform this method:
Turn on the component tester.
Put the resistor (1K that I used above) you want to test in the socket of your tester.
Press the test button.
See the results on the screen.
If the resistor is good it will show you its value. If it is bad, it will tell you that the resistor is bad – it is that simple.
The limitation of this method is you can not use it for in-circuit resistance testing.
Other than that it is a very easy and straightforward method to apply. It will save you a lot of time and resources.
2. Capacitor testing
A capacitor is another fundamental level component. It has two terminals and acts as a passive energy-storing device.
It has two types. The electrolytic and the ceramic type.
The electrolytic type capacitors are polarity dependent meaning that they have positive and negative terminals.
While ceramic capacitors are independent of polarity. You can connect them in the circuit without worrying about their positive or negative terminals.
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