Linear

A linear element is an electronic component that has a linear relationship with the current or voltage in an electronic circuit. Resistors are the most common example of linear elements, along with capacitors and inductors. A linear element is one in which the output quantity is proportional to the input quantity. For example, in the case of constant temperature, the relationship between the voltage and current at both ends of a metal resistance element can be considered to be linear. Metallic conductors and electrolytes also have this property.