A two-terminal electronic component made of a resistive material and having a certain structural form and capable of limiting the passage of current in the circuit. A resistor cannot be changed and is called a fixed resistor. A variable resistance is called a potentiometer or a variable resistor. The ideal resistor is linear, ie the instantaneous current through the resistor is proportional to the applied instantaneous voltage. Some special resistors, such as thermistors, varistors, and sensitive components, have a non-linear relationship between voltage and current. Resistors are the most widely used components in electronic circuits. They are usually formed in different series according to power and resistance for circuit designers to choose. The resistor is mainly used in the circuit to regulate and stabilize the current and voltage. It can be used as a shunt and a voltage divider, or as a circuit matching load. According to the circuit requirements, it can also be used for the negative feedback or positive feedback of the amplifier circuit, voltage-current conversion, voltage or current protection components when input is overloaded, and can also constitute RC circuit as oscillation, filtering, bypass, differential, integral and time constant. Components, etc.