Wollaston wire

The wire is named after its inventor, William Hyde Wollaston, who first produced it in England in the early 19th century.^[1] Platinum wire is drawn through successively smaller dies until it is about 0.003 inches (0.076 mm, 40 AWG) in diameter. It is then embedded in the middle of a silver wire having a diameter of about 0.100 inches (2.5 mm, 10 AWG). This composite wire is then drawn until the silver wire has a diameter of about 0.002 inches (0.051 mm, 44 AWG), causing the embedded platinum wire to be reduced by the same 50:1 ratio to a final diameter of 0.00006 inches (1.5 μm, 74 AWG). Removal of the silver coating with an acid bath leaves the fine platinum wire as a product of the process.

Wollaston wire was used in early radio detectors known as electrolytic detectors ^[2] and the hot wire barretter. Other uses include suspension of delicate devices, sensing of temperature, and sensitive electrical power measurements.

It continues to be used for the fastest-responding hot-wire anemometers.