A resistor can become non-ohmic, meaning it does not obey Ohm’s law (V = IR), due to various factors that alter its resistance with changes in voltage or current. One common cause is temperature dependency. Resistors made from materials whose resistivity changes with temperature can exhibit non-ohmic behavior. For example, as the temperature of a resistor increases, its resistance may increase or decrease, deviating from the linear relationship predicted by Ohm’s law.
Another factor causing non-ohmic behavior is the material’s intrinsic properties. Certain materials, such as semiconductors or components with complex internal structures, may show nonlinear resistance characteristics under different voltage or current conditions. This nonlinearity can arise due to changes in the carrier concentration or mobility within the material when subjected to varying electrical stimuli.
An object becomes non-ohmic when its resistance does not remain constant with changes in applied voltage or current. This behavior can be caused by physical changes within the material structure, such as heating effects, or due to intrinsic properties like semiconductor behavior or nonlinear resistance elements.
An example of a non-ohmic resistor is a semiconductor material used in temperature-sensitive applications, where the resistance varies significantly with temperature. In such cases, the resistor’s resistance does not follow Ohm’s law strictly because it changes with temperature variations, making it non-ohmic.
Some resistors do not obey Ohm’s law because their resistance varies nonlinearly with changes in voltage or current. This non-ohmic behavior can occur due to factors like temperature effects, material composition, or the physical structure of the resistor. Understanding and characterizing non-ohmic resistors is crucial in circuit design to ensure accurate operation and reliable performance under varying conditions.