Capacitance is nothing but a resistance offered by a capacitor to the flow of electrons is called capacitance. It just stores and releases the electrons for some interval. Example: Power electronics circuits, Power factor correction devices, electronics devices.
In this article, we are going to see, capacitance formula, energy stored in capacitor formula, capacitor series connection formula, capacitor parallel connection formula, and significance.
Capacitance formula for Two Parallel Plates:
Capacitance across a capacitor C(F) in farad is equal to the permittivity times of the surface area A(m2) in square meter divided by the distance between the two plates d(m) in the meter. The formula can be written as,
C(F) = ε x A (m2) / d(m) ————————-1
Farad = permittivity x area / distance between the plates.
Here capacitance will be measured by farad. But farad is the very largest unit of capacitance. Hence you can find the smaller size capacitor in microfarad or Milli farad.
Here the permittivity ε is equal to the relative permittivity ε(r) times of the permittivity of free space ε (0).
ε = ε(r) x ε (0) ———————-2
Apply 2 in 1, and then the capacitance equation can be written as,
C(F) = ε(r) x ε (0) x A (m2) / d(m)
Also, the capacitance C(F) in farad is equal to the ratio between electric charge Q(c) in coulomb to the potential difference between the plate V(V) in volts. The formula will be,
C(F) = Q(c) / V(V)
AC capacitance formula:
The AC capacitor is used to pump reactive energy to the power system to improve the power factor for reducing the line loss. Here the capacitance C(µF) in microfarad is equal to reactive power in kVAR divided by the 6.28 times of frequency and voltage square. Hence the capacitance formula can be written as,
C (µF) = KVAR / (2 x π x f x V2)