Patent ID: 7157982

Claim:
A Wien-Robinson oscillator ( 10 ) having an operational amplifier ( 15 ), having a negative feedback path which is formed from two resistors connected in series and in which the first resistor ( 16 ) is arranged between the reference ground potential and the inverting input of the operational amplifier ( 15 ), and the second resistor ( 17 ) connects directly to the output ( 18 ) of the operational amplifier ( 15 ) and is arranged between the output ( 18 ) of the operational amplifier ( 15 ) and its inverting input, having a positive feedback path, which is formed from two RC elements connected in series, in which the first RC element ( 20 , 21 ) is arranged between the reference ground potential and the non-inverting input of the operational amplifier ( 15 ), and in which the second RC element ( 22 , 23 ) is connected at one end to the non-inverting input of the operational amplifier ( 15 ) and at the other end is connected via a common circuit point ( 26 ) to a third resistor ( 25 ), wherein the common circuit point is connected via the third resistor ( 25 ) to the output ( 18 ) of the operational amplifier ( 15 ), with the first RC element being formed from a first capacitor ( 21 ) and a fourth resistor ( 20 ) connected in parallel, and with the second RC element being formed from a second capacitor ( 23 ) and a fifth resistor ( 22 ) connected in series, having a first diode ( 30 ) via which the common circuit point ( 26 ) is connected to a constant positive auxiliary voltage (+Uk1), and having a second diode ( 31 ), via which the common circuit point ( 26 ) is connected to a constant negative auxiliary voltage (−Uk1), with the magnitudes of the two auxiliary voltages (+U k1, −Uk1) being the same, and the diodes ( 30 , 31 ) being connected such that they limit the voltage (Ua 2 ) at the common circuit point ( 26 ).