A capacitance is the circuit element in which the energy is stored in the electrostatic field. The physical device producing capacitance known as a capacitor. The capacitor is formed by inserting a dielectric (insulating) material between the two conducting surface or plates.
- a capacitance is defined as the property of the device by which it carries a current when voltage is changed w.r.t time.
- The capacitance C is symbolically represented.
- When a time –varying voltage ‘v’ is applied across the capacitance ,it carries a time –varying current ‘i’.
- This current is proportional to the rate of change of voltage w.r.t time.
i ∝ dv/dt or i= C dv/dt
where C is the constant of proportionality which is known as the capacitance of the device.
As i =C dv/dt, V=1/C ∫idt
i.e v∝idt or v ∝ charge q
Thus for capacitance , the voltage is proportional to the charge.
The capacitance is measured in farad(F).