= Membrane capacitance
{title2=$C_m$}
<Membrane capacitance> is the <capacitance> associated with separated <electric charge> across <cell membrane>. A local ideal <capacitor> has charging <electric current> $I_C=C_m\,dV/dt$. If a known actual membrane voltage change is $\Delta V$, integrating the charging transient after subtracting sustained ionic and leak components gives $C_m=\Delta V^{-1}\int I_C\,dt$. Pipette <capacitance>, finite <patch-clamp series resistance> and imperfect transient subtraction can bias the estimate. A capacitive transient is not by itself an <ion channel> opening.
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