Doorbell

Older door bell

Nineteenth century electric doorbells in an apartment block

A doorbell is a device which is typically installed to or near a door. When a visitor presses a button, the bell rings inside the building, alerting the presence of the visitor.

In modern technology, a button is pressed completing a circuit which in response makes a sound.

History

Older doorbells were fully mechanical. Newer electrical doorbells were installed by wires and use a push-button to activate the sound. The latest doorbells have wireless connections although older ones may be wired.^[1]

Doorbell Media

Doorbell at the entrance of Chetham's Library, Manchester, England
Sound of a two-tone mechanical doorbell
Doorbell mechanism from 1884 in Andrássy Avenue, Budapest
Old door bell pull knobs in Edinburgh, United Kingdom. It is unclear whether bells were rung by wire and pulleys, or by electrical connection.
Wireless doorbell with piezoelectric button