The resistance of a conductor to the current is called the resistance of the conductor. Resistance is a physical quantity, which indicates the size of the resistance of a conductor to current in physics. The greater the resistance of the conductor, the greater the resistance of the conductor to the current. Different conductors have different resistance. Resistance is a property of conductor itself.
导体对电流的阻碍作用就叫该导体的电阻。电阻（Resistance，通常用“R”表示）是一个物理量，在物理学中表示导体对电流阻碍作用的大小。导体的电阻越大，表示导体对电流的阻碍作用越大。不同的导体，电阻一般不同，电阻是导体本身的一种性质。导体的电阻通常用字母 R 表示，电阻的单位是欧姆，简称欧，符号为Ω。
The resistance of a conductor to the current is called the resistance of the conductor. Resistance (usually expressed by “R”) is a physical quantity, which indicates the resistance of a conductor to current in physics. The greater the resistance of the conductor, the greater the resistance of the conductor to the current. Different conductors have different resistance. Resistance is a property of conductor itself. The resistance of a conductor is usually represented by the letter R. the unit of resistance is Ohm, abbreviated as Ohm, and the symbol is Ω.
金属导体中的电流是自由电子定向移动形成的。自由电子在运动中要与金属正离子频繁碰撞，每秒钟的碰撞次数高达 1015 左右。这种碰撞阻碍了自由电子的定向移动，表示这种阻碍作用的物理量叫作电阻。不但金属导体有电阻，其他物体也有电阻。导体的电阻是由它本身的物理条件决定的，金属导体的电阻是由它的材料性质、长短、粗细（横截面积）以及使用温度决定的。
The current in a metal conductor is formed by the directional movement of free electrons. Free electrons frequently collide with positive metal ions in motion, and the number of collisions per second is about 1015. This kind of collision blocks the directional movement of free electrons, and the physical quantity indicating this blocking effect is called resistance. Not only metal conductors have resistance, but other objects also have resistance. The resistance of a conductor is determined by its physical conditions. The resistance of a metal conductor is determined by its material properties, length, thickness (cross-sectional area) and service temperature.
Resistor is called resistor directly in daily life. It is a current limiting element. After the resistor is connected to the circuit, the resistance value of the resistor is fixed. Generally, it has two pins, which can limit the current through the branch connected to it. A fixed resistor is called a fixed resistor. Variable resistance is called a potentiometer or variable resistor. The ideal resistor is linear, that is, the instantaneous current passing through the resistor is proportional to the applied instantaneous voltage. Variable resistor for voltage sharing. One or two movable metal contacts are pressed tightly on the bare resistor body. The contact position determines the resistance value between any end of the resistance body and the contact.
端电压与电流有确定函数关系，体现电能转化为其他形式能力的二端器件，用字母 R 来表示，单位为欧姆Ω。实际器件如灯泡，电热丝，电阻器等均可表示为电阻器元件。
The terminal voltage and current have a definite functional relationship, reflecting the ability to convert electrical energy into other forms of two terminal devices, expressed by the letter R, in ohm Ω. Practical devices such as light bulb, heating wire and resistor can be expressed as resistor elements.
The resistance value of a resistance element is generally related to temperature, material, length and cross-sectional area. The physical quantity measuring the resistance affected by temperature is the temperature coefficient, which is defined as the percentage of resistance value change when the temperature increases by 1 ℃. The main physical characteristic of resistance is to change electrical energy into heat energy, which can also be said to be an energy consuming element. The current passing through it will produce internal energy. Resistance usually acts as voltage divider and shunt in the circuit. For signals, both AC and DC signals can pass through resistance.