Working Principle of Hot-Wire Instruments

Working Principle of Hot-Wire Instruments Points : Working Principle of Hot-Wire Instruments The working principle of these instruments depends upon the increase in length of wire due to heating effect when current proportional to the square of the current passed through the wire. The increase in length of the wire at operating temperature is of course, only a very small percentage of its total length. Various mechanical linkages have been devised to magnify this motion and convert it to motion of a pointer on a circular scale.