torsion hygrometer

torsion hygrometer

[′tȯr·shən hī′gräm·əd·ər]
(engineering)
A hygrometer in which the rotation of the hygrometric element is a function of the humidity; such hygrometers are constructed by taking a substance whose length is a function of the humidity and twisting or spiraling it under tension in such a manner that a change in length will cause a further rotation of the element.