RC and LCR circuits, oscillations and resonance

Charge a capacitor from a cell, then join it to a coil. The capacitor starts to discharge, but the coil opposes any quick growth of the current, so the current rises gradually. When the capacitor is empty, the current is at its largest and all the energy is in the magnetic field of the coil. The current cannot stop at once: the self-induced emf of the coil, which opposes the fall of the current, keeps it going and charges the capacitor again, now the other way round. When the capacitor is full again, the current is zero and the energy is back in its electric field. Then everything repeats in the opposite direction. The energy swings between the electric field and the magnetic field. The wires have some resistance, which turns a little energy into heat in every cycle, so the swings get smaller: the oscillation is damped. The circuit oscillates at its natural frequency f = 1 ÷ (2π√(LC)), with L in henry and C in farad. A larger L or C gives a lower frequency. Use π = 3.14 and convert mH and µF first.