How To Test Transistor Without Multimeter (2024)

Hi there! Looking for the answer to learn how to test transistor without multimeter? Then, you are at the right article.

In this short article, we together will explore a solution that you can try to test transistors without using any kind of multimeter.

And by testing, I mean to tell if it is a bad or good transistor as well. If it is a good transistor, then what is its right pin configuration. Moreover, we will also get to know the type of BJT transistor as well, i.e. if it is NPN or PNP.

I hope you will enjoy this article and will find answers to your question.

Table of Contents

Why do we need to test transistors?

The first question is, why do we need to test or check a transistor in the first place. The answer is simple, to check if it is a good transistor or a bad one.

Because there is no point in using a bad transistor in the circuit as it will lead you to inaccurate results. And sometimes this may also damage other connected components due to overvoltage or overcurrent flow.

But why without using a multimeter?

The answer is, just because we can, and we are keen learners. There is no such other technical reason I can think of – like if I am an electronics guy, why wouldn’t I have a multimeter.

If I don’t have a multimeter, then I should think about whether I am a real electronics person or I am just playing around.

The other possible answer can be, that we want to know if we have other options as well. But again as I said we are keen learners.

How To Test Transistor Without Multimeter?

You know, to be honest, I really don’t think it is possible to test a transistor without a multimeter time efficiently. If you don’t want to use a multimeter, then you have to use other alternative devices.

But you got to have a measuring device to properly check and test any type of transistor.

Yes, you can design some kind of checker circuit to check a transistor, but I will leave that for some other blog article.

So, to check a transistor with no multimeter, there are two methods you can follow:

1- Using a professional level oscilloscope with a component testing option
2- Using a dedicated transistor tester

Oscilloscope with a component testing option

This first method is expensive and is best for people who are professionals and work with electronics boards with a bunch of transistors.

This method is really recommended when you want to test transistors in-circuit without desoldering them from the board.

Dedicated transistor tester

Now, this method is really time efficient and reliable. This will save you a lot of time if you are the guy working with transistors.

For this method to be applicable, you need to have a decent transistor tester. You can buy from anywhere as they are not expensive and all the transistor testers are pretty much the same.

Following is the transistor tester, which I personally like. It is a very basic one, but it does the job very well.

The good part of this tester is you can use it for various other components as well. It is like all in one component tester.

Let’s see how you can use this tool to test any transistors.

How to use a transistor tester to test a transistor?

First, take the transistor you want to test. Let’s say you want to test a BJT transistor and let’s say you don’t know if it is NPN or PNP. You do not know its DC beta value. You also do not know its right pin configuration i.e. which pin collector, emitter, or base.

To know all the above parameters of transistor we need to have a dedicated transistor tester which we talked about above.

The transistor tester which we will use is the M328 transistor tester (Amazon link). Follow the following steps:

Turn on the transistor tester first, you should see the screen light up.
Put the component socket in the proper place in the transistor tester
Now take you transistor you want to test
Place it in the component socket in any configuration
Push the test button
And you should see the results on the screen.
The results will tell if it is NPN or PNP, it will tell you its DC beta value, and it will also show you the right pin configuration.

You see this little device gives us all the important information about a transistor in like no time thus saving our precious time.

Now, if the transistor is bad, the screen will show you no results or will tell you no component found. These are the indication you are working with a bad transistor. You need to get rid of it immediately.

Conclusion

We need to know as engineers and students how to test transistor without multimeter. We need to know how many other ways are there that we can use to check transistors of any type.

Because to me, it doesn’t make any sense how we can test a transistor without using a multimeter. Except that we are keen learners and want to explore things.

So, there are three ways you accomplish this:

Design a checker circuit
Using an oscilloscope with a component testing feature
Use a dedicated transistor tester

This first one is technical and needs domain expertise. This is why I have decided to create a separate article on this some other time.

The second method is expensive and geared towards more professional-level work. Also, this method is helpful if you want to test transistors while they are still soldered to the circuits, i.e. in-circuit transistor testing.

The last method is suited for the majority of us. As it is cheap and is very reliable in the long run.

In this method, we use a dedicated transistor tester to tell us the type of transistor, and various useful related parameters, but importantly it tells us if the transistor is bad or good.

In the end, I would say. I am not perfect, nor is this article. But my intention is to share something that might be useful to some of you. I tried my limited knowledge best to create something. I hope it will help you somehow, maybe a little. But that would be enough for me.

I hope you enjoyed it.

Thank you and have a great life.