Doorbell Overview: Wired, Wireless, and Smart video bells.

A doorbell is a signalling device comprising a transformer, chime and a push button. It is a security device that signals users when a visitor is at the front door.

When the visitor presses the push button, the chime rings inside the house to alert users.

In 1817, a Scottish inventor, William Murdoch, invented the first mechanized doorbell that operates on a system of pipes and compressed air.

As technology improved, Joseph Henry invented an electric doorbell in 1831. These modern doorbells use a push button to work. They also use intercoms and video cameras to increase security.

Why is doorbell useful?

Doorbells play some useful roles in our home security system.

  • They signal the user when a visitor is at the front door
  • The video bells capture every movement around your home and also allow the user to watch it on his/her mobile phone.
  • Allows you to speak with your visitor even when you are away from home.

Types of doorbell

There are three basic types of doorbells and they include:

  • Wired doorbells
  • Wireless doorbells
  • Smart doorbells.

Wired doorbells

In a wired system, the wiring starts from the press button at the front door, connects to the transformer, and then the buzzer, or chime.

Related post: How to wire a doorbell.

When you press the push button, it closes the circuit. This allows the current to flow into the electromagnetic system of the bell. The magnetic field produced by the electromagnet causes the metallic bars in the bell to strike, producing the “ding dong” sound you hear.

But for a bell to work properly, it needs a transformer. The transformer steps down the household current of 120 volts to about 8 to 20 volts required by a doorbell.

Similar post: How to find a doorbell transformer.

Wireless doorbells

A wireless doorbell doesn’t need a wiring system to work, rather a press button and a buzzer.

While it saves you the expense of wiring the doorbell, it also has an inbuilt battery that may not last. The push-button has an inbuilt radio transmitter powered by a battery which, when pressed, sends a radio signal to the receiver unit usually plugged into a wall outlet in the house.

Once the receiver unit detects the signal, it plays a “dig-dong” sound via a loudspeaker.

You can also install a wireless doorbell application on your phone to monitor your home.

Example of wireless doorbell is the Zumimall doorbell.

Smart doorbells

Since the emergence of the internet, several internet doorbells known as smart doorbells have evolved.

Popular among them are:

The smart doorbells usually installed in our homes comprise a press button, HD video camera, passive infrared sensor, and Wi-Fi electronics. They are connected to the home Wi-Fi-network.

When it detects movement around the front door or the button pressed by a visitor, it signals the paired smartphone..

Users will have to receive signals to see video coverage of the visitor at the door, and they can have a 2-way audio discussion..

The recorded video is stored in the internet cloud and can be retrieved even if the smart bell is damaged or stolen.


1. Are doorbell transformers AC or DC?

Doorbell transformers and all other forms of transformers use alternating currents. Transformers don’t use direct current because they are direct, stable, and cannot produce current. There must be a relative motion between a conductor and the magnet to produce the current.

Read the working principles of an electrical transformer here.

2. Are doorbell wires dangerous?

Doorbell wires are of low voltage between 8 – 24 volts and cannot shock you. The household currents, which are dangerous, are usually stepped down to low voltage by the bell transformer before use.

3. Can a doorbell transformer go bad?

Yes, it can, but not as often as you may think. When your bell stops working, many things could be responsible. It may be the chime, push-button, and sometimes the transformer. So, be sure the fault is from your transformer before changing it.

Here is more information on how to test a doorbell transformer

Doorbell, not loud enough. What can I do?

There is nothing you can do other than replace the transformer if it is a wired doorbell, but for wireless doorbells, you can increase the volume and also upgrade the chime.

Best doorbell for the deaf

since the deaf cannot hear a ringing bell, special doorbells with loud and visual alerts are made for them.

The bell comes with bright flashing lights and an extra loud bell that will surely make the deaf notice the presence of the visitor. An example is physen doorbell.

My doorbell keeps ringing, why?

If your chime keeps ringing, especially on a wired doorbell, know that the button is stacked.

Or that the button wires joined. Lose the push button and correct the error.

About mariaelectricals

Hi, I am Emmanuel Nwankwo, a commercial electrician and the founder of I established this blog to share my decades of work experience in electrical installations and repairs.