Wollaston wire

From Wikipedia, the free encyclopedia

Wollaston wire is an obsolete name for very fine (less than .01 mm thick) platinum wire used for electrical instruments around the turn of the 19th century.

[edit] History

The name referrs to the person who developed the early technique for producing such fine wire. Platinum wire was drawn through smaller and smaller dies until it was about .003 inch in diameter. It was then embedded in the middle of a silver wire having a diameter of about one-tenth inch. This composite wire was then drawn until the silver wire had a diameter of about .002 inch; as the platinum wire within it was reduced in the same ratio, it would be drawn down to a final diameter of .00006 inch (1.5 μm). Removal of the silver coating with an acid bath left the fine platinum wire as a product of the process. The term Wollaston wire did not clearly distinguish the bare platinum wire from the composite silver wire with a fine platinum core.

[edit] Uses

Wollaston wire was used in early radio detectors known as electrolytic detectors. Other uses include suspension of delicate devices and sensing of temperature.

Today Wollaston wire is used in temperature sensors and sensitive electrical power measurements.

[edit] Sources

Sources include scientific suppliers[¹] where it is extremely expensive.