Conductance and its Relation

Conductance:
The conductance of a material is its property which tells us with how easily current can flow through that material. In simplest way it is defined as

“Reciprocal of resistance is called conductance.” It is denoted by G and is given by

G=1/R

Unit:

The unit of conductance is mho or siemen and is represented Ʊ.

Relation:

As conductance is reciprocal of resistance so it is inversely proportional to the length of the conductor but directly proportional to the area. According to above statement

G α 1/L ........(1)

G α A ...........(2)

By combing above two relations we have

Gα A/L

or

G= σ A/L

where σ= Conductivity and is defined as

Conductivity:

The reciprocal of resistivity is called conductivity. It is represented by σ.

Unit:

The unit of conductivity is mho per meter(Ʊ/m) or siemen per meter.

Alternatively

As we know that
R= (ρL)/A ....(1)
Also
R=1/G .......(2)

By comparing (1) & (2), we get
1/G=(ρL)/A

On simplifying
G=1/ρ(A/L)
where
1/ρ= σ=Conductivity.

Comments

Alternating Quantity

Alternating Quantity: Any quantity that changes its magnitude with respect to time is called alternating quantity.In electrical engineering it is known as alternating voltage or current and is defined as below "If the polarity of the voltage changes with time, it is known as alternating voltage and the current caused by such a voltage is called an alternating current." Consider the following figure. The above figure explains that voltage or current increases with time to a certain specific value which is called peak or maximum value and after that it decreases even to reach starting position i.e 0 in our case. As time goes on the quantity reverses its direction and increases to again that maximum value which it reached out in the positive half cycle but with negative sign. After that it again follow decreasing and finally reaches the starting position again.This is the way that alternating quantity repeat itself again and again. Mathematically, v=...

Relationship between Resistance and its physical dimensions

As conductor is made up of some material that will have certain dimensions such as length and area etc that plays a part in calculating the resistance. The resistance of a conductor depends on the following parameters 1:Length of conductor 2:Cross-sectional area of conductor 3:Resistivity 4:Temperature of the conductor Now we will explain all of above four parameters one by one . Length and Area of conductor : The resistance of material is directly proportional to the length of the conductor but inversely proportional to the area of the conductor. We know that when length of a material increases its area will decrease which means path or channel through which electrons flow will decrease. Under such a condition more collision will occur resulting in increase of resistance.Mathematically, ...

Carbon Resistors

Carbon Resistors: A component whose function in a circuit is to provide a specified value of resistance is called a carbon resistor. A carbon resistor is manufactured by baking a powdered carbon mixed with a binding material. This results in a small tube with a wire attached to both ends. The range of carbon resistor is from a fraction of an ohm to several million ohms. The power rating of a carbon resistor depends upon the physical size of the resistor. Power rating means the electrical by consumed by a component or converted into another form of energy by that component. In our case resistor is going to be discussed so a large resistor is able to dissipate more energy into heat than a smaller one which means larger resistor consumes more power and that is why its power rating is high. Color coding scheme: A color code is printed on a carbon resistor which gives us information about the resistance of that resistor. In this scheme generally a carbon resistor has four band...

Electrical Engineering

Search This Blog