Abstract: Device for providing a magnetic field for transfer of energy A device for providing an inductive power transfer (110, 210). The device comprises a switching power supply (VI) for providing electrical power to the device and an inductor coil (140). The device further comprises a resonance adjustment module (110) for adjusting the resonance frequency of the circuit comprising the inductor coil and a control circuit arranged to control the module such that the resonance frequency is substantially constant. The mutual and leakage inductance of a transmitter coil and of a receiver coil change if the receiver coil is placed above the transmitter coil. The circuit is utilised for inductive power transfer to a vehicle, possibly in a parking space.