A magnetic field for application to body tissue is generated via a first inductor. Connecting circuitry, including at least first and second branches, is provided between a capacitor arrangement comprising at least a first capacitor, and the first inductor. A switch forming part of the first branch electrically connects the capacitor arrangement to the first inductor enabling electrical current to flow through the first branch and the first inductor, thereby causing the first inductor to generate the field. The current flowing through the first branch represents a first direction of flow between the capacitor arrangement and the first inductor. An electric component conducts current primarily in a forward direction. That component forms part of the second branch, enabling current to flow between the capacitor arrangement and the first inductor through the second branch. The flow in the forward direction represents a second direction opposite the first. The capacitor of the capacitor arrangement has a variable capacitance.