the layout and op amp have some phase shift, the capacitor has a 10% tolerance, and temperature introduces more errors. When I built the circuit with the specified components, it oscillated at 542 Hz.

from a wave with zero degrees of phase shift. The t parameter, of course, is time in seconds. If you think about a sine wave, it is really showing a point on a moving and rotating circle.

The recent Design Idea “Getting an audio signal with a THD < 0.0002% made easy,” discloses a low THD sine generator which led me to dust off a design that I ... Variations in the oscillation with ...