Capacitance

#Physics

$\displaystyle C\equiv \frac{Q}{V}$

  • The capacitance between two charges on separate conductors
  • $\displaystyle V$ is the voltage

$Q=CV,\space C=\frac{Q}{V},\space V=\frac{Q}{C}$

  • Units of capacitance $C$ are $\text{Farad }(\frac{C}{V})$
  • The capacitance is dependent only on the geometry of the capacitor, and not the voltage or charge held.

$U_C=\frac{1}{2}CV^2=\frac{1}{2}QV=\frac{Q^2}{2C}$

$C_\text{plates}=\kappa\varepsilon_0\frac{A}{d}$

  • $\kappa$ is the dielectric constant
  • $\displaystyle {\varepsilon}_{0}$ is the permittivity of free space
  • $A$ is the area of a single plate
  • $d$ is the distance between the plates

$C_\text{plate}=\varepsilon_0=\frac{A}{d}$

  • Check this later

$C_\text{series}=\left(\displaystyle\sum_{i=0}^N\frac{1}{C_i}\right)^{-1}$

$C_\text{parallel}=\displaystyle\sum_{i=0}^NC_i$