导体中电流I和电压U的关系可以用图线来表示,用纵轴表示电流I,用横轴表示电压U,画出的“I-U图线”称之为导体的伏安特性曲线.电流跟电压成正比时,伏安特性曲线是通过坐标原点的直线,具有这种伏安特性的电学元件称之为线性元件,伏安特性曲线不是直线的 The relationship between the current I and the voltage U in the conductor can be represented by a graph line. The vertical axis represents the current I, the horizontal axis represents the voltage U, and the drawn IU graph is called the conductor volt-ampere characteristic curve. When the current is proportional to the voltage, the volt-ampere characteristic curve is a straight line passing through the origin of the coordinate. The electrical component having this volt-ampere characteristic is called a linear element, and the volt-ampere characteristic curve is not a straight line.