Question

What is a variable resistance? Explain its function using a labeled diagram.

Answer 1

Variable resistors consist of a resistance track with connections at both ends and a wiper which moves along the track as you turn the spindle. The track may be made from carbon, cermet (ceramic and metal mixture), or a coil of wire (for low resistances). The track is usually rotary but straight track versions, usually called sliders, are also available.
Variable resistance is a device used to change the resistance and hence the current flowing through a circuit; without changing the voltage.