To begin, let's look at a circuit that has only a capacitor and an inductor. We shall pretend that these components are ideal, ie that they have no internal resistance. In practice this is not possible: there will always be some way in which electrical energy can be converted to heat, even if the rate is very small. We begin by charging the capacitor C with an initial charge qo. (In the demonstration shown in the photograph above, we did this by connecting the capacitor to a battery, then disconnecting it.) We then connect the capacitor to an inductance L, as shown below, and analyse the current i that flows and the voltage V across the components.