Regarding its basic electronic component function, it is to impede the flow of electric current. The two most fundamental parameters for measuring a resistor are resistance value and power rating. The resistance value indicates the degree to which the resistor impedes current, measured in ohms. In addition to the basic unit, there are kilo-ohms and mega-ohms. The power rating indicates the maximum current the resistor can withstand, measured in watts, with ratings such as 1/16W, 1/8W, 1/4W, 1/2W, 1W, 2W, etc. Exceeding this maximum value will cause the resistor to burn out. Based on the manufacturing materials, resistors include cement resistors (low production cost, high power, high thermal noise, unstable resistance value **, and poor stability), carbon film resistors, metal film resistors (small size, stable operation, low noise, high precision), and metal oxide film resistors, among others. Depending on whether the resistance value is adjustable, they can be classified as trimmer resistors, variable resistors, potentiometers, etc.