I-U characteristics

In the case of electronic components and circuits where there is a dependence between current and voltage, this can be represented in an xy diagram. From such a diagram, conclusions can be drawn directly from the physical quantity current to the quantity voltage, or vice versa.

I-V characteristics of linear and non-linear resistors

With the I-V-characteristic, the current is represented in the vertical, the voltage in the horizontal, therefore this characteristic is also called the current-voltage-characteristic. In the case of an ohmic resistor, the characteristic curve corresponds to a straight line because there is a linear relationship between current and voltage.

The situation is different in the case of non-linear dependence, for example in the case of PTC thermistors and hot conductors, diodes, Zener diodes, tunnel diodes, transistors, incandescent lamps, light-emitting diodes, solar cells and many other components.