What are the functions of the three contacts of a potentiometer? Do the three contacts have different resistances? How do I measure the resistance of each contact?

A potentiometer is a common electronic component. It has three contacts: two fixed contacts and one sliding contact. Each contact plays a different role in the potentiometer and has a different resistance value.

First, let's understand the basic structure and principle of a potentiometer. A potentiometer consists of a resistor bar made of conductive material and a sliding contact connected to the resistor bar. When the sliding contact moves along the resistor bar, it forms a resistive path of varying lengths between it and the resistor bar, thereby changing the resistance value in the circuit and adjusting the resistance.

In a potentiometer, the fixed contacts are often called end contacts, while the sliding contact is called the middle contact. The end contacts are generally connected to the two ends of the resistor bar and serve to limit the range of movement of the sliding contact. Their resistance value is usually fixed and does not change with the movement of the sliding contact.

The center contact is the most critical point in a potentiometer; its position determines the resistance value. In potentiometer design, the sliding contact is typically placed at one end of the resistor strip and can move along the strip. When the sliding contact approaches a fixed contact, the potentiometer's resistance approaches that of the fixed contact; when the sliding contact approaches another fixed contact, the potentiometer's resistance approaches that of the other fixed contact.

The resistance of each contact can be measured using a measuring instrument such as a multimeter. First, connect the potentiometer to the measuring instrument, ensuring that the measuring instrument's electrodes are in contact with the contacts. Then, move the sliding contact to the appropriate position for the contact to be measured. Finally, select the appropriate resistance measurement range on the measuring instrument and perform the measurement. The measurement result is the resistance value of the corresponding contact.

It is important to note that when performing resistance measurements, the power supply should be disconnected and no current should be flowing through the potentiometer. Furthermore, avoid using excessive measuring voltage to avoid damaging the potentiometer.