Breakdown-limited parallel-plate charge ($Q_{\max }=ϵA{E}_{\mathrm{bd}}$)

For an ideal uniform dielectric between large parallel plates, $Q=CV=(ϵA/d)(Ed)=ϵAE$. A prescribed breakdown field $E_{\mathrm{bd}}$ therefore limits charge independently of plate separation. Voltage capacity still grows with separation. This ideal result neglects field enhancement near edges and any dependence of the breakdown field on gap geometry or environmental conditions.