Maybe you can adapt something like this?
Manipulate[
bump[t_] := Piecewise[{{0, t < 50}, {1, t >= 50}}];
soln = NDSolve[{Q''[t] == (-R*Q'[t] - (Q[t]/C1) + Vo)/L + bump[t],
Q[0] == 1, Q'[0] == 0.5}, {Q[t], Q'[t]}, {t, 0, 100}];
Plot[Evaluate[Q'[t] /. soln], {t, 0, 100}, PlotRange -> All],
{R, .1, 1.50}, {C1, 1, 50}, {L, 1, 50}, {Vo, 1, 40}]
