The invention relates to a transmitting or receiving resonant circuit (2) for transmitting power contactlessly through inductive resonant coupling with a transmitting receiving resonant circuit (1), having a first capacitance (C1) and a first winding (E1), the first winding (E1) having an inductance (L1) and a first resistance (R1), the transmitting resonant circuit (2) having a second capacitance (C2) of value C2' and a second winding (E2), the second winding (E2) having a second inductance (L2) of value L2', a second resistance (R2) of value R2', the transmitting resonant circuit (2) having an eigenpulse u>2 such that w2 = 1/V (L2' x C2') and an eigenfrequency f2 such that f2 = w2/(2-rr), characterised in that the inductance value of the second inductance (L2) varies in a predetermined manner.