RC Op-amp Oscillator (Phase-Shift Oscillator)
Using an RC lead-lag (phase shift) network and op-amp, a sinusoidal waveform oscillator can be created. The figure below shows an example of the phase shift oscillator. There are three RC networks and a feedback loop. When the total phase amounts to 360 degrees, oscillation occurs. The frequency of the oscillation is determined by the sizes of the R and C.