The main function of a resistor is to resist the flow of current. It is used in current limiting, current shunting, voltage reduction, voltage division, load and capacitor matching as filters, and impedance matching. Resistors are non-polar components, and their resistance values can be identified by color bands or engineering codes on the component body.When selecting a resistor, it is important to choose the correct resistance value and tolerance. Pay attention to the resistor's limiting parameters, such as rated voltage and rated power. Prioritize general-purpose resistors for ease of procurement and maintenance, and select based on the circuit's characteristics.Different resistors have varying resistance values and functions, so they should not be substituted for one another indiscriminately.