Episode 2 of 2

Patent Application

When: 4 November 1879
Where: Menlo Park
Part of: Edison's incandescent lamp: carbonized-thread test, patent application and first public demonstration

Edison filed for U.S. Patent 223,898 on 4 November 1879 for a coiled carbon filament lamp.

Edison filed for a patent on 4 November 1879 for an electric lamp using a carbon filament or strip coiled and connected to platina contact wires. The patent described several ways of creating the carbon filament, including using cotton and linen thread. It was granted on 27 January 1880.

Sources

Thomas Edison Wikipedia, revision of 2026-10-04
Incandescent light bulb Wikipedia, revision of 2026-09-23

Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.