http://www.angelfire.com/ab9/tsking/in.gif I have several question to ask? 1)why the voltage oscillates and amplitude decrease ? 2)how the frequency be affected by varing capacitance value and removed double c core ? 3)what is the corresponding physical quantities between spring -mass oscillation and electical oscillation? I have a few ideas: 1)since the capacitor is fully charged,when the switch isset to discharge the capacitor,there is a sudden increase in current in the inductor,B-field is induced ,then the induced current is inversely return to the capacitor,in this process ,energy is dissipated,thus V oscillate,A decrease 2)because f=2 (pi)(1/LC)^1/2 thus L or C increase ,resulted in f decrease 3)m/k=1/LC ???