EducationHow to test a transformer with a multimeter

How to test a transformer with a multimeter

Category articles

Do you know how to test a transformer with a multimeter? If not, don’t worry, this blog post will walk you through the process step-by-step! Testing a transformer is an important part of keeping your devices up and running. 

Without properly functioning transformers, your electronics could come to a standstill. That’s why it’s important to know how to test them and identify any problems early on.

Here you can find more multimeter tutorials.

What is a transformer and how does it work?

Transformers are electrical devices that change the voltage of an alternating current (AC) signal. They do this by converting AC power to either high-voltage or low-voltage signals. This is important because it allows for the safe transmission of electricity over long distances.Transformer can also be used to step-up or step-down the voltage of an AC signal before it enters a building.

Transformers come in different sizes and shapes, but how they work is always the same: by creating a magnetic field around two coils of wire called windings. One winding is connected directly to an alternating current source (such as a power line) while the other winding is connected to an electrical load (such as light bulbs).

When current flows through one coil, it creates a magnetic field around both coils. As long as there are no gaps in between these two windings, they will always be opposite polarities – i.e., one will have North facing up and the other will have South facing up.

This is what creates the alternating current in the transformer. By varying how much current flows through each winding, you can change the amount of voltage that is output by the transformer.

Primary and secondary

The primary and secondary of a transformer are the two coils of wire that create the alternating current.

The primary is the coil that is connected to the power line, while the secondary is the coil that is connected to the electrical load. By varying how much current flows through each winding, you can change the amount of voltage that is output by the transformer.

How to test a transformer with a digital multimeter?

Now that you know how transformers work, let’s take a look at how you can test them using a digital multimeter.

To do this, first set your meter to read AC voltage (not DC). Then connect the black lead from your meter to one of the output terminals on the transformer and use an alligator clip or other similar device to connect it securely.

Next, touch both probes together and set your meter to read resistance (ohms). You should get a reading of 0 ohms.

Now, touch the red probe to one of the input terminals and take a reading. You should get a reading of either 120 volts or 240 volts, depending on how your transformer is wired. If you don’t get a reading, there may be a problem with how your transformer is wired.

If all goes well you’ll see that the transformer has an impedance rating of anywhere from 0-100 ohms (depending on how much current it’s designed to carry).

If your meter doesn’t read anything at all, then something else could be wrong such as wire breaks inside the transformer or an open circuit in one of its output terminals.

Identifying problems in transformer

Now, how do you know if there is a problem with your transformer? There are several ways to identify this and it all depends on how much time you have available for testing them.

For instance, if only one side of the transformer is not working, you may be able to hear a humming noise when you touch the probes together. This is because there is no current flowing through the transformer and it’s trying to work against itself (sort of like how your heart races when you hold your breath).

You can also test for continuity by checking whether or not there is a path through which electricity can flow from one point of contact to another. If there isn’t any path for current, then that means something has happened inside your transformer and needs fixing!

The best way to identify problems in transformers is by using a digital multimeter. It’s easy enough how-to test them with these devices; just follow the steps above. If all goes well you’ll be able to identify any problems that might exist within your transformer and how-to fix them so they work properly again!

You should also check other circuits parts, because all the parts of the electrical circuit are connected together.

Conclusion

In this article we learned how they work, how to test a transformer with a multimeter, and how do you know if there is a problem with your transformer?

Hope that you find this article useful. If you have any questions or comments please leave them below and I’ll be more than happy to help you out!

Michal Pukala
Electronics and Telecommunications engineer with Electro-energetics Master degree graduation. Lightning designer experienced engineer. Currently working in IT industry.

News