I'm new to the subject of oscillators and learned that sustained sinusoidal oscillations are made possible by positive or regenerative feedback. Is that right? If that's true then I can't quite grasp why, especially in op-amp LC or RC oscillators, is the feedback network terminated to the inverting input while the non-inverting input is usually grounded. Doesn't it make it negative feedback? My circuit analysis ability is not yet fully developed so please bear with me.
Also, I would highly appreciate if someone patiently traces out the operation of this particular colpitts oscillator for me in relation to this question.
One more thing: does the LC network act as the feedback or it's just a tank circuit while Rf entirely serves as the feedback? I know. silly questions.