The terms "linear" and "nonlinear" conductors refer to how the electrical conductivity of a material behaves in response to changes in applied electric field or voltage. Let's break down the differences between linear and nonlinear conductors:
Linear Conductors:
Linear conductors are materials that exhibit a linear relationship between the applied electric field (voltage per unit length) and the resulting current flowing through the material. In other words, if you plot the current versus voltage for a linear conductor, you'll get a straight line that passes through the origin (0,0). The conductivity of linear conductors remains constant regardless of the magnitude of the applied electric field within its operating limits.
Ohm's Law is a fundamental principle that describes the behavior of linear conductors:
Ohm's Law: V = I * R
where:
V is the voltage across the conductor,
I is the current flowing through the conductor,
R is the resistance of the conductor.
In linear conductors, resistance (R) remains constant as long as the temperature and other physical conditions remain constant.
Nonlinear Conductors:
Nonlinear conductors, on the other hand, do not follow Ohm's Law and have a nonlinear relationship between the applied electric field and the resulting current. This means that the conductivity of the material changes as the electric field strength changes. In other words, the resistance of the material is not constant and can vary significantly with voltage or current.
Nonlinear conductors often exhibit a phenomenon called "negative differential resistance." This means that as the voltage increases, the current decreases, which is opposite to what is observed in linear conductors.
Nonlinear conductors are commonly used in devices like varistors, thermistors, and certain types of diodes, where their nonlinearity is intentionally exploited for specific applications.
In summary, the key difference between linear and nonlinear conductors lies in their response to changes in applied electric field or voltage. Linear conductors follow Ohm's Law and have a constant resistance, while nonlinear conductors exhibit a nonlinear relationship between voltage and current, leading to changing resistance values as the applied voltage changes.