In this video, NEM Director Mike Simons and Educator Sam Parker demonstrate the carbon arc lamp. Sir Humphrey Davy invented the carbon arc lamp – the first electric light source – in the early 19th century in England. The carbon arc lamp predates Edison’s incandescent light bulb by about seventy years. As you will see in the video, when the two electrified carbon rods touch, some of the carbon vaporizes. As you pull the carbon rods away from each other, the current flows through the vaporized carbon in the air gap, resulting in an arc of intense light.
Arc lamps were installed in public spaces, as they were brighter and cheaper than gas or oil lighting. Because carbon arc lamps were extremely bright, they were mainly used for city street or industrial lighting, and in public venues such as hotels and theaters.
There were drawbacks to the carbon arc lights. One was that the carbon electrodes burn out very quickly, requiring the carbon rods to be replaced every few hours. Another drawback was that the carbon arc lights created an uncomfortable environment: they buzzed loudly and flickered, released carbon monoxide, and emanated harmful ultraviolet light. Also, due to the high heat and sparks emitted they were a fire hazard. With the rise of the incandescent lightbulb and its safer and more comfortable light, use of arc lamps declined by the first few decades of the 20th century.
