Twin-T oscillators can be used to produce sinusoidal signals in the audio track with good performance. The circuit shown in the figure is an example of a double T oscillator for the audio track using a type 741 operational amplifier. The twin-T components determine the operating frequency of the oscillator at the same time as the 100k ohm potentiometer on the reference circuit determines the symmetry of the generated signal and, therefore, its distortion. Note that the power supply must be symmetrical and that the output is made through a 1 uF capacitor. Depending on the application and the frequency range, this capacitor can be changed or even eliminated.
