Abstract :
In an oscillator with nearly sinusoidal voltage, the change ΔI1, of the fundamental component of current owing to the presence of higher harmonic voltage components Vn, can be expressed as a function of Vn. It is shown that the relation for Im ΔI1corresponds to Groszkowski´s law of reactive power balance of harmonics. An interesting relation between Re ΔI1and the sum of real powers of the higher harmonics is found.