% Verbal description for system CM (CM_desc.tex)
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The acausal bond graph of system \textbf{CM} is
displayed in Figure \Ref{CM_abg} and its label
file is listed in Section \Ref{sec:CM_lbl}.
The subsystems are listed in Section \Ref{sec:CM_sub}.
{\bf CM} is an electromechanical moving-plate capacitor with linear
electrical capacitance $c$ of the form
\begin{equation}
c = c_0 \frac{x_0}{x}
\end{equation}
where $x_0$ is the plate separation corresponding to a capacitance of
$c_0$.
The corresponding electrical constitutive relationship (which gives an
energy-conserving two-port \textbf{C}) is
\begin{equation}
F = Q c_0 \frac{x_0}{x^2}
\end{equation}
where $F$ is the force between the plates and $Q$ the charge on the
capacitor.
This is implemented in the \emph{cm.cr} Constitutive Relationship.