Complex sentence: The potentiometer is a satisfactory way for non critical applications such as volume control on a radio, but as it has a wiper contact rubbing against a resistance element, dirt and wear between the wiper and the resistor can cause erratic readings.
Split into simpler sentences: The potentiometer is a satisfactory way for non critical applications such as volume control on a radio, but as it has a wiper contact rubbing against a resistance element. Dirt and wear between the wiper and the resistor can cause erratic readings.