How Can I Test My Doorbell Transformer?

For you to ask how to test a doorbell transformer, it could either mean your video doorbell is not working, or you want to know the voltage of your transformer.

Whichever one it is, I will show you how to test a doorbell transformer with a multimeter.

For those that are still looking for their transformer location, see how to find a doorbell transformer.

The primary role of a doorbell transformer is to step-down a household current from 120 V to about 16-24 volts it requires.

When a doorbell system stops working, many things could be responsible. It may be the push button at the front-door, the doorbell chime, or the transformer. So make sure you find out the cause before assuming that your transformer has gone bad.

Signs of a bad transformer

You can hardly tell if a transformer is bad unless you test it with a multimeter. A reading of 16 -24 volts shows that the transformer is working fine.

If the voltage is Less than 16, call an electrician to replace the transformer because it has gone bad. .

How to test a doorbell transformer with a multimeter

Testing a transformer is easy, anybody can do it. All it requires is a functional multimeter and a doorbell transformer.


  • ON your multimeter and set the knob to a low voltage setting, often 25 AC volts.
  • Place the probes from the multimeter on each screw head of the transformer.
  • Read the voltage level on your multimeter.
  • If it is between 16-24V AC, it is ok, but if the voltage is less than 16, change the transformer.

Can I check the voltage level of my doorbell transformer without a multimeter?

Yes, you can do that by looking at the body of your transformer, you will see their voltage rating. However, it can only be useful for new transformers, as you cannot use the method to troubleshoot a faulty transformer.

My doorbell stopped working, what could be the cause?

Many things could be responsible. It may be your doorbell chime, your push button, or your doorbell transformer. Troubleshooting the system will surely find out the cause.

While troubleshooting starts with the push button because they are the part that spoils often in a doorbell.

Loose out the push button on the door and bring out the wires from the button. Join the two wires.

If the bell rings, you know you have found the fault. If not, check the chime.

Loose the chime’s cover, set the knob of your multimeter to be on voltage, and touch the probes on the wires. Ask someone to press the button for you. If the multimeter shows that the current is flowing but the bell is ringing, replace it.

If the chime is good, test the transformer. If one of them is the cause, just replace it.

Is doorbell transformer AC or DC?

All transformers use AC current, which is in line with faradays law of electromagnetic induction. Doorbell transformers are no exception to the rule.

Also, your home uses AC. Converting it to DC will require an additional rectifier that may be more complex and expensive.


You’ve seen it all, including how to test a doorbell transformer and ways to troubleshoot faulty doorbells. apply each technique as we used it in the article.