This?
.----. | | _V_ | .----|___|--o----. | | | \\] \\] \\] | o--|]---|]---|]--o | /]+ /]+ /]+ | | | | |\\ | '----|-\\ | | >--------o-------- .--|+/ | |/ | === GND (created by AACircuit v1.28.6 beta 04/19/05
That's not a phase-shift oscillator, because there aren't enough independent caps for the phase shift to happen. For a phase shift oscillator you need a schematic like this:
_ | \\ | \\ out .----------|-K >-----------------o-------- | | / | | |_/ | | | | | | ___ ___ ___ | '--o--|___|--o--|___|--o--|___|--' | | | | | | --- --- --- --- --- --- | | | | | | === === === GND GND GND (created by AACircuit v1.28.6 beta 04/19/05
where (IIRC) the amplifier has a negative gain that's greater than 29. One very important thing that's different here is that the capacitors are not independent -- each one "talks" to the other through resistors. This could also be done with a series chain of capacitors _as long as_ you have resistors going to ground at the end of each capacitor -- think of the figure above with the resistors and capacitors swapped.