Re: Random thoughts on sinewave oscillators

On Sat, 19 Oct 2024 20:13:12 +0100, piglet <erichpwagner@hotmail.com>
wrote:

On 18/10/2024 4:46 pm, john larkin wrote:

On Fri, 18 Oct 2024 11:25:19 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
 

"piglet" <erichpwagner@hotmail.com> wrote in message news:vetde5$38sbk$1@dont-email.me...

Edward Rawde <invalid@invalid.invalid> wrote:

>
The circuit below produces a reasonable looking sinewave but the rise
time still seems to be slower than the fall time. It may be that the
amplifier in use is not ideal for this.
>

>
Could that just be second harmonic distortion? You could test the amplifier
by uncoupling the Wien network and injecting test inputs.
>
Elsewhere I think your amplitude control problems could be simply due to
too much gain.

>
Perhaps, but I've not so far been able to get the circuit I posted in response to Bill to produce a sine wave no matter what I do
with the control loop gain.
It either grows to clipping or dies.
>

>
>
--
piglet

>

 
I do a lot of instant-start LC oscillators as the timebase of
triggered delay generators. I let them clip just a bit to stabilize
amplitude.
 

>
>
Here is an amusing oscillator that has a voltage follower as the active
stage - it has no voltage gain so some people say it cannot work - they
are wrong of course.

This is a sort-of-Colpitts (not quite) oscillator that uses a BUF602
unity-gain buffer amp. Phase noise is pretty good.

https://www.dropbox.com/scl/fi/ffeer8ocqwyaeobh49zh7/BUF602_LC_Osc.jpg?rlkey=xl6pt8sjz7y6hhgynnloj1f36&raw=1

The BUF part is much better than any discrete transistor would be.