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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: Final final 1kHz oscillator Date: Sat, 9 Nov 2024 23:27:46 +1100 Organization: A noiseless patient Spider Lines: 53 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sat, 09 Nov 2024 13:28:01 +0100 (CET) Injection-Info: dont-email.me; posting-host="78505003f26acfb61046862908a2f911"; logging-data="3968042"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+vBIzyQnslq6JcyAv5OQwoS8sZzbZeLwc=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:Y1hfp1COpXbmgChHHN6wt3BCTMU= Content-Language: en-US X-Antivirus-Status: Clean X-Antivirus: Norton (VPS 241109-2, 9/11/2024), Outbound message In-Reply-To: Bytes: 3353 On 9/11/2024 7:39 pm, Edward Rawde wrote: > "Bill Sloman" wrote in message news:vgn4gm$3lcor$1@dont-email.me... >> 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? > > Yes > >> >> 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? >> > > When I cut and pasted the file into notepad++ and removed line 391 and subsequent lines (or fixed wraps) and under encoding > converted to ANSI everything worked fine. > >> 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 > > You'd have to take that up with the LTSpice parts library. You put that parts in. >> I presume you intended u or the Greek mu symbol, and after I'd done that substitution the simulation did work, if not well. > > No substitution is required if you convert to ANSI in notepad++ Perhaps. >> 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. In fact I also had to take out C6 and R9. Once I'd done that the circuit simulated a lot faster, and settled down after about 20 seconds. The next 20 seconds showed a third harmonic spike about 60DB below the fundamental - respectable but not great. Putting too much delay into a feedback loop makes it unstable - that's what Bode plots are all about. -- Bill Sloman, Sydney -- Bill Sloman, Sydney