kooldraad
Kooldraad is a historical Dutch term for carbon-based conductors used in early electrical technology. The word combines kool, meaning coal or carbon, with draad, wire, and appears in late 19th- and early 20th-century Dutch technical writing. Because it was used by different authors to describe various carbon-containing conductors, its exact scope varied by source.
Carbonized filaments and graphite rods were produced from natural fibers or coal-tar products. Carbon conductors offer
With the wider adoption of copper and insulated metal wires, kooldraad usage declined. Today it survives mainly
Manufacturing historically involved pyrolysis of organic precursors (such as cellulose fibers or pitch-based materials) in oxygen-free
See also: carbon filament, graphite, carbon fiber, electrical resistance heating.