Abstract: A circuit arrangement is provided with a controlled switch which is controlled by means of a periodic switching signal for operating an oscillation circuit at a frequency f, and with a control circuit for generating the periodic switching signal. The control circuit comprises a pulse width generator for generating a periodic square wave signal with a half cycle duration which is adjustable in steps of a value T and which has a value of at least t. The circuit arrangement is characterized in that, with 2*(t+N1*T)<1/f<2*(t+(N1+1)*T) in which N1 is an integer number, the periodic switching signal is built up from a repetitive chain of square wave signals with a repetition cycle which comprises n1 half cycles of a duration t+N1*T and n2 half cycles of a duration t+N2*T, wherein N2 is >N1 and is an integer number.