AVR-Chat

At 08:51 AM 3/14/2004 -0500, John Johnson wrote:


>On Sunday, Mar 14, 2004, at 08:45 US/Eastern, David VanHorn wrote:
>
>> At 08:38 AM 3/14/2004 -0500, John Johnson wrote:
>>
>>> Not to split hairs here, but the two caps will never be equal.
>> Or are you making the case, that like two resistors, they may be 
>> 0.001% off no matter how carefully they match them?
>
>Yes. I was implying that if the two caps have to be unequal for 
>oscillation to start, it will always start.

They do NOT have to be unequal.
Where does that idea come from?

In order to have oscillation, you need only these things:

Gain > 1.0
Phase shift at frequency of interest, 180 degrees.
and a closed loop.