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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: Final final 1kHz oscillator
Date: Sat, 9 Nov 2024 18:54:46 +1100
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On 9/11/2024 7:43 am, Edward Rawde wrote:
> This is the simplest circuit I can come up with.
> Harmonics are more than 80dB down in simulation.
> FFT the last 30 seconds.
> There is only one harmonic stopping me claiming 90dB but the exact FFT result can depend
> on exactly how much output is selected for the FFT. You may see different results.
> 
> If a prototype is ever built, attention to the type and quality of the capacitors used will be needed.
> Electrolytics are not intended. Put C1 and C2 near U1 supply pins.

If electrolytics are not intended, why are most of the capacitors rated 
at 10V?

When I cut and pasted the file the capacitors were mostly labelled as 
10?, 1? and - in the case of the wein bridge capacitors 0.015?

The 15nF capacitors are rated at 16V - the polypropylene parts you can 
actually buy that are offered with a +/-1% tolerance are 63V and 250V parts

I presume you intended u or the Greek mu symbol, and after I'd done that 
substitution the simulation did work, if not well.

The feedback loop doesn't settle well, and I suspect that I know why. R4 
should probably be in series with C3, not in parallel.  More later.

-- 
Bill Sloman, Sydney
-- 
Bill Sloman, Sydney