Difference Between Conductivity and Conductance

Conductivity vs Conductance
 

Conductance and conductivity are two valuable properties in physics. In this article, we are going to discuss only electrical conductance and electrical conductivity, which are two significant concepts in electrical and electronic engineering. This article covers the definitions, similarities, and finally the difference between electrical conductance and electrical conductivity.

Conductance

To understand conductance, one must first understand the resistance of an object. Resistance is a fundamental property in the field of electricity and electronics. The resistance in a qualitative definition tells us how hard it is for an electrical current to flow. In the quantitative sense, the resistance between two points can be defined as the voltage difference that is required to take a unit current across the defined two points. The resistance of an object is defined as the ratio of the voltage across the object to the current flowing through it. The resistance in a conductor depends on the amount of free electrons in the medium. The resistance of a semiconductor mostly depends on the number of doping atoms used (impurity concentration). The resistance a system shows to an alternating current is different from that to a direct current. Therefore, the term impedance was introduced, to make AC resistance calculations much easier. The Ohm’s law is the single most important law when the topic resistance is discussed. It states that for a given temperature, the ratio of voltage across two points, to the current passing through those points, is constant. This constant is known as the resistance between those two points. The resistance is measured in Ohms. The conductance of a component is a measurement of how easily a current can flow through the component. The conductance is defined as the inverse of resistance. The conductance is measured in Siemens (S). It must be noted that electrical conductance is a property of the component itself.

Conductivity

The resistance of a component depends on various things. The length of the conductor, the area of the conductor, and the material of the conductor are to name some. The conductivity of a material can be defined as the conductance of a block having unit dimensions made out of the material. The conductivity of a material is the inverse of the resistivity. Conductivity is usually denoted by the Greek letter σ. The SI unit of conductivity is Siemens per meter. It must be noted that conductivity is specifically a property of the material at a given temperature. The conductivity is also known as specific conductance. The conductance of a component is equal to the conductivity of the material multiplied by the area of the material divided by the length of the material.