Warning: mysqli::__construct(): (HY000/1203): User howardkn already has more than 'max_user_connections' active connections in D:\Inetpub\vhosts\howardknight.net\al.howardknight.net\includes\artfuncs.php on line 21
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