The resistance of the potentiometer is either 5 kΩ or 10 kΩ. It has four taps, among which three taps are closely spaced. The single tap serves as the grounding terminal. Two of the three taps are the two ends of the potentiometer, and the other one is the center tap of the potentiometer. The specific meanings of each terminal of the potentiometer can be seen in the diagram at the bottom of the potentiometer.

For a single potentiometer, if you can’t distinguish the taps, use the ohmmeter function of a multimeter to measure the resistance between each pair of terminals. You’ll find that there is one terminal whose resistance values to the other two terminals are exactly half of the total resistance of the potentiometer (regardless of the rotation of the central shaft). This terminal is the grounding terminal, the other two terminals are the two ends of the potentiometer, and the remaining terminal is the center tap.