In electronics Resistance is defined as “the opposition of a body or substance to current passing through it”. It’s measured in Ohms. The resistor (see above), is a passive electrical component that creates resistance in the flow of electric current. In almost all electrical networks and electronic circuits they can be found. However in guitars we use a potentiometer, or pot, which is actually a variable resistor. This means as the knob shaft is rotated, the resistance will change. A pot is very simple by design, and once we review the components and their purpose they should be less mysterious.
There are three lugs or soldering terminals on a conventional potentiometer (see diagram above). The outside two are the ends of the resistive element, and the center lug is connected to the “rotating dial.” The rotating dial allows you to vary the DC resistance relative to its position along the resistive strip. Typical guitar pots have ratings in Ohms such as 25K, 250K, 300K, 500K, and 1Meg. This is how you can determine a pot’s value.