Capacitance refers to the ability of a capacitor to store energy in an electric field. This energy is stored by the use of an electronic component called capacitor. The Capacitance is denoted by the symbol 'C'. The charged amount is determined by the capacitance C and the voltage difference V applied across the capacitor. The capacitor contains a pair of plates, in which when a steady voltage is applied across a capacitor, a +Q charge is stored in one plate and - Q is stored on the opposite plate. The SI unit of capacitance is farad (F), where one farad is equal to one coulomb per volt.
Capacitance :
C = Q/V
Electrical Charge :
Q = CV
Potential Difference :
V = Q/C
Where,
C = Capacitance,
Q = Electrical Charge,
V = Potential Difference
The capacitance, "C", of a capacitor is defined as the ratio of the magnitude of the charge on either conductor to the potential difference between the conductor. The capacitance is proportional to the area of its plates, whereas it is inversely proportional to the distance between the plates.
Example:
Calculate the Capacitance when electric charge and potential difference are known.
Electrical Charge (Q) = 25 C
Potential Difference (V) = 20 V
Solution:
Apply Formula:
C = Q/V
C= 25/20
C = 1.25F
Capacitance(C) =1.25 F