Difference btwn standard resistance n rheostat
Answers
Resistance is a passive element in electrical and electronic circuits. It has several applications in both DC and AC circuits. Its main property is it is a power consuming element, and opposes the flow of current. Resistance elements are available as resistors of main two varieties-
1- Fixed resistors of various types like wire, carbon, metal oxide etc. Their values are fixed once made.
2- Variable resistance-These change their values depending upon construction and properties of materials.
Most common variable resistance is Potentiometer, mainly made from carbon tracks, used for low power circuits and as variable potential dividers.
Potentiometer type high power variable resistors made from wire wound on core, and mainly used for high power are called rheostats. A slider moves over a resistance element, making contact at different points along its travel. Resistance between this point and one end terminal this varied.
Rheostst is mainly used as variable resistance, and not as potential divider. Power consumption is quite high, so the resistance is wound on ceramic core.
Earlier answer gives good details about rheoststs. I have written to clarify the difference between resistance and rheostat