<p>The oscillator uses a three-terminal active element (1), such as a FET with both series feedback (25) and parallel feedback (29). The series feedback comprises an inductive (26) and a capacitive (27) element. The parallel feedback comprises a further capacitive element (28). The starting of the oscillator is thereby improved, while output power is increased and the influence of impedance fluctuations of a load (30) is reduced.</p>