I simulated this op amp oscillator with LTSPICE but was a bit surprised that the output was a square wave rather than a sinusoid. It is a dual supply op amp with 3 RC networks between the output and the inverting terminal.
To make it I simulated the RC network cascade and saw where the transfer function phase crossed 180 degrees. I was expecting oscillation to happen there at 3.9 kHz, but it actually occurred at
3.04 kHz. I had assumed that the op amp doesn't add phase, but maybe I should look at the phase transfer function in the circuit with the caps removed.Perhaps I need to shoot for a higher frequency if I want a sinusoid?
R1 Vout 3 10k C1 3 0 10n R2 2 1 10k C2 1 0 10n R3 3 2 10k C3 2 0 10n XU1 0 1 VCC VEE Vout LT1001 V1 VCC 0 2.5 V2 0 VEE 2.5 .tran 2m startup .options method=trap .lib LTC.lib .backanno .end