What is the functions of capacitors in oscillators.
1. One they provide 180 phase shift along with oscillator combined.

Won't these capacitors interfere in oscillator operation by providing low resistance path to ac signals?

 

First, what kind of oscillator are you talking about. There are several.

 

oscillators which we use in MCU for clock.

 

oscillators which we use in MCU for clock.

These oscillators can and probably should be approached with a "Simon sez" mental outlook: just follow what the data sheet says and don't over think it.

Those caps form part of the feedback network and are required to get the proper phase shift so the dang thing oscillates in the first place.

 

I am also interested in this topic.
How exactly do they (the capacitors) contribute to the feedback.

Could you (or somebody) please explain it in more details?

I searched for this info for a long time but could not find much about the role of the capacitors . (I mean explained in more details )

Thank you

 

Hello,

Take a look at the attached PDFs.

Bertus

 

The caps in most oscillators are part of a resonance circuit when combined with another component(s). But in crystal oscillators they are not part of the timing components. They are there, depending on exact configuration, to block DC, pass the Osc freq, or provide AC feedback, maybe even providing damping for the crystal.

Just follow the data sheets...there's more to them there crystals than we know....

 

What's the difference b/w crystal oscillator & pierce oscillator?

 

Hello,

From Wikipedia, the free encyclopedia


The Pierce oscillator is a type of electronic oscillator particularly well-suited for use in piezoelectric crystal oscillator circuits. Named for its inventor, George W. Pierce (1872-1956),[1][2] the Pierce oscillator is a derivative of the Colpitts oscillator. Virtually all digital IC clock oscillators are of Pierce type, as the circuit can be implemented using a minimum of components: a single digital inverter, two resistors, two capacitors, and the quartz crystal, which acts as a highly selective filter element. The low manufacturing cost of this circuit, and the outstanding frequency stability of the quartz crystal, give it an advantage over other designs in many consumer electronics applications.

Here is the complete wiki page:
http://en.wikipedia.org/wiki/Pierce_oscillator


Bertus