Variable resistors, like potentiometers and sliders, are symbols used to represent electronic components that adjust electrical resistance. These resistors allow for manual or automated control of the flow of electricity, making them essential in applications ranging from volume adjustment in audio systems to speed control in motors. The symbol consists of an angled line with an arrow indicating movement, representing the adjustable aspect of the resistor. The terminals extend from the angled ends, connecting the resistor to the circuit and enabling resistance variations.