Re: opamp sine wave oscillator

On Mon, 4 Feb 2008 19:21:15 -0800 (PST), Inventor
<Inventor-66@xxxxxxxxxxx> wrote:

On Feb 4, 10:13 pm, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Mon, 4 Feb 2008 18:49:21 -0800 (PST), MooseFET <kensm...@xxxxxxxxx>
wrote:



On Feb 4, 2:32 pm, Inventor <Inventor...@xxxxxxxxxxx> wrote:
Hi, hope I'm posting to the right place. I created a nifty little
sine wave oscillator. I have no plans to patent it just want to tell
the world about it cause I think it's pretty cool. You can download
the pdf file here:

http://www.freedomodds.com/osc/

I like it for lots of reasons, but what's more important is peer
review. So what do you think of my nifty little oscillator?

It has way too many parts in it.

10K
-------/\/\------------
! !
+-------!-\ LT1013 !
! ! >--------+---+----- Out
! GND--!+/ !
=== === 1.0u
! 0.1u !
GND GND

Your circuit has way too many parts.

-----------------------
! !
+-------!-\ AD840 !
! >------------+----- Out
GND--!+/

John

Thanks for your input, John. It does seem like a lot of parts, but
when you look at the alternatives, in most cases, it is fewer parts.
But yeah, four RC's for a single oscillator does seem like a lot. If
you want fewer parts try the LC oscillator described later in the
paper I guess.

The "alternatives" have more parts for reasons. If you just let an RC
oscillator build up amplitude until it clips, you get a lot of
distortion. If you clip just a tiny bit, it's marginal to oscillate at
all.

Hewlett's lightbulb was a nonlinear element with a long gain time
constant that rolled off the gain to get stable amplitude with low
distortion.

An LC oscillator can be made with mimimal parts and low distortion,
but it's hard to tune over a wide range.

All this was understood 70 years ago.

John



.

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