L \left[ U(t) + {W'(t)}/{W(t)} \right]  \label{RtI} \end{aligned}$$ within the fitted range of times while $I(t)$ may be distinguished from noise. Likewise, for the voltage data the approximation $$\begin{aligned}
   \label{Vapprox} 
\left| R C' + L C'' \right| \ll 1 \end{aligned}$$ simplifies the differential equation (\[Vde\]) to $$\begin{aligned}
V'' + \left( \frac{R}{L} + \frac{2C'}{C} \right) V' + \left( \frac{1}{LC} \right) V \approx 0. \end{aligned}$$ In this case, the circuit parameters may be estimated as $$\begin{aligned}
 \label{CtV}
C(t) &\approx 1/[{L \, W(t)}] \\
R(t) &\approx L \left[ U(t) + {2 W'(t)}/{W(t)} \right], \label{RtV} \end{aligned}$$ again, within the fitted range of times while $V(t)$ may be distinguished from noise. For both cases, after estimating $C(t)$ and $R(t)$ the initial approximation, either (\[Iapprox\]) or (\[Vapprox\]), must be tested for consistency.

  ---------------------- --------- --------- ----------------- -------------
  [Data set]{}             $A_0$    $\tau$    $\omega/(2\pi)$      $t_0$
                            Amp     $\mu$s          kHz           $\mu$s
  MC with discharge       16.7(2)   15.1(2)     279.64(14)      $-$0.030(6)
  MC without discharge    14.4(2)   13.5(2)     277.96(15)      $-$0.036(6)
  ---------------------- --------- --------- ----------------- -------------

  : \[tab:1\] Fixed RLC fit parameters for data in Figs. 3 and 7 using the form (\[FixedRLC\]). The offset $I_0$ is excluded. Values in parenthesis are uncertainties in the last digits. The variation between parameters with and without discharge is 