How to Find and Test a Doorbell Transformer.

Maybe your doorbell stopped working or you want to upgrade it to a ring smart pro or nest doorbell. Locating your doorbell transformer is not always easy.

But as a doorbell expert, I will guide you on how to find a doorbell transformer location easily.

What is a doorbell transformer?

A doorbell transformer is an electrical machine that steps down the household current from 120 V to about 16-24 volts required by smart doorbells.

It is a brass- or silver-colored box of about 2 to 3 inches square, containing two to three terminal screws on the face.

It can be installed anywhere in the house, but most electricians fix it at the electrical panel or inside the circuit breaker.

Once you locate the transformer, troubleshooting or upgrading to a smart doorbell can be easy.

Below is a guide on how to locate a smart bell transformer.

Related article: How to test a doorbell transformer

How to find a doorbell transformer.

While some transformers can be located inside the doorbell’s chimes or bell enclosure, others can be elsewhere. Below are the places to find your bell transformer.

Doorbell transformer location number one: electrical panel.

The electrical panel is the most common place to locate your doorbell transformer. This is because of its open nature, it also hastens replacement if the transformer spoils.

It is usually the best place to look for your doorbell transformer, however, not all electricians install the transformer there.

Doorbell transformer location number two: Garage

We have seen many transformers installed in the garage, this is because of their easy access.

Normally, a doorbell transformer is surface mounted to avoid overheating.

While looking for your transformer in the garage, check around the front door, communication cables, or near any outlets in your garage hopefully, you will see it.

But if you do not, never lose hope. Instead, check the next location.

Transformer location number 3: Near the security system.

Sometimes, the doorbell transformers are located near the security system. So while looking for your transformer, look around the security system. Check near the system keypad and the control station and it might be there.

Also, some security systems such as the intercom have the transformer tied inside them.

Transformer Location Number 4: Closet.

Your closet is also a good place to look for your transformer. Look inside the closet, check above the closet door and on the front wall, it might be there.

Check your furnace closet

Look above the closet door and along the walls, you might see the bell transformer.

Check the attic or basement.

Gain access to the attic and check around the front door and above the doorbell location.

Look beneath the stairs in the basement, the transformer may be there.

Check beneath your stairwell

Look under the stairwell of a two-story building and if you have a storage area under the stairs, check it. Some installers fix the transformers in such a hidden area.

Testing the smart bell transformer

Once you have seen the location of the transformer, testing it quite easy. First check the wiring system of the doorbell to know if it is correct.

To check the wiring, see our article on how to wire a doorbell.

If the wiring system is correct, check the transformer with a digital multimeter to know if it is functional.

For details on how to test a transformer, read our article on how to test a doorbell transformer.


Because I have seen what some people pass through just to locate their smart bell transformer, I have made a list of all the places to search for your transformer. Just look for your transformer in the above places and hopefully, you will see it.

To buy a new doorbell, get it here at Amazon

Related articles: How to wire a doorbell transformer