Capacitors and capacitance


1) Capacitor is a system of arrangement of conductors which can store electric charge.


2) Upon electric charge store it also develops potentials proportionately.


3) Suppose for a Q amount of charge storage, the capacitor develops V amount of potential then,



4) here C is proportionality constant called capacitance of the capacitor.


5) Capacitor, capacitance unit is Farad.



6) Capacitor in electric circuit is denoted as


Having fixed amount of capacitance.


7) The capacitors which have variable capacitance are denoted as





Parallel Plate Capacitor


Charging of capacitor:


 


1) Suppose there are two parallel plate conducting plate X & Y.


2) X & Y are separated by a medium which is non-conductor of electricity, e.g. air medium, glass, mica. Etc.


3) Suppose X is charged with positive charges of amount q

4) Then same q amount of negative charge will also be developed by induction to the plate Y.


5)  +q amount of charge will also develop on the farther face of the plate Y.


6) Now if Y plate is connected to the earthened, then the excess positive charge will flow to the earth and there will only be -ve the charge on the plate Y.


7) Now plate X & Y  are only positive & negatively charged.


8) This process will lower the potential of the system.


9) Low potential means more electric charge can be stored.


10) This is how capacitors can be charged.