Path: ...!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: Instead scopes
Date: Sat, 31 Aug 2024 01:39:37 +1000
Organization: A noiseless patient Spider
Lines: 70
Message-ID: <vasp45$hnfl$2@dont-email.me>
References: <val7f8$33hu3$1@dont-email.me>
 <8f2tcj1832r0m6872hvp1fcrv8hsf3chsh@4ax.com> <vam90i$3bn2f$1@dont-email.me>
 <gjeucj5a7skeruudj8qcujc1f9b9t9o26r@4ax.com> <vanf8s$3h5er$1@dont-email.me>
 <mtjucjdqe2f91c2jsjp6011k0uvakuimog@4ax.com> <vap20i$1s5cl$1@solani.org>
 <8dv0djhj73b0ejudpkahnojgjk30i9rrbv@4ax.com>
 <je01dj177m9p0q25en4k2jm8u0bsj07t2j@4ax.com> <vaq1f2$jdj$1@dont-email.me>
 <vaq762$1ssg1$1@solani.org> <pcg1djt6otqheh6vgi9len892jd21g1sn0@4ax.com>
 <varpuq$1sgha$1@solani.org> <1ak3dj9pbeivllh8jk5ke2ani3jid2hl3p@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Fri, 30 Aug 2024 17:39:50 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="ed1659357dd9c5ce14643d010d7e66dc";
	logging-data="581109"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19ZtT8ROLatwKFROLkFpdfVr2AK2hFtvDA="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:qPoHXGD353y75W6yt04up7XZWtA=
X-Antivirus-Status: Clean
Content-Language: en-US
In-Reply-To: <1ak3dj9pbeivllh8jk5ke2ani3jid2hl3p@4ax.com>
X-Antivirus: Norton (VPS 240830-4, 30/8/2024), Outbound message
Bytes: 4678

On 31/08/2024 12:13 am, john larkin wrote:
> On Fri, 30 Aug 2024 06:47:54 GMT, Jan Panteltje <alien@comet.invalid>
> wrote:
> 
>> On a sunny day (Thu, 29 Aug 2024 11:47:42 -0700) it happened john larkin
>> <jl@650pot.com> wrote in <pcg1djt6otqheh6vgi9len892jd21g1sn0@4ax.com>:
>>
>>> On Thu, 29 Aug 2024 16:21:21 GMT, Jan Panteltje <alien@comet.invalid>
>>> wrote:
>>>
>>>> On a sunny day (Fri, 30 Aug 2024 00:43:39 +1000) it happened Bill Sloman
>>>> <bill.sloman@ieee.org> wrote in <vaq1f2$jdj$1@dont-email.me>:
>>>>
>>>>> It's lot easier and quicker to bread-board a circuit in LTSpice than it
>>>>> is to wire up a test circuit, but what that means is that you need to
>>>>> make fewer real circuits and they are a lot more likely to work when tested.
>>>>>
>>>>> That, on it's own, is enough to explain why labs look different today
>>>>> than they did in the dark ages.
>>>>
>>>> All it explains is boeings falling apart and astronuts ending up stuck at the ISS
>>>> and no moonlanding from the US, not even a probe.
>>>
>>> The ISS and moon landings are super-expensive theatre. Neither
>>> accomplishes anything.
>>>
>>> Boeing and Microsoft have the same problem, bean counter money-mongers
>>> have taken over from engineers.
>>>
>>>> Slimulations are _not_ realty and never will be.
>>>
>>> Spice can be very handy. As Mike says, LT Spice's real function is to
>>> train your instincts.
>>
>> I dunno, much I learned from working with tubes and transistors was by building small circuits and measuring what happened.
>> Sure spice is great for math intensive stuff such as filters.. but you still need to know the basics.
>> These days with chips doing much of the work and limited knowledge what is actually _in_ those chips
>> it is hard to tell if a real circuit will behave like spice tells you
>> You will still need real testing.
> 
> Sure, but if I wake up at 3AM in Truckee, I can Spice an idea and go
> back to bed.
> 
> https://www.youtube.com/watch?v=x6TrbD7-IwU&list=PLlD2eDv5CIe9u7jbKUkZ5xrLLSCrn0z_e
> 
> Actually, I have designed useful circuits by randomly fiddling with
> Spice, stupid topologies that turn out to work.

What a creationist would call intelligent design. The rest of us call it 
evolving your circuits, rather than designing them, and you have 
described that as insanely inefficient.

>> Maybe boeing just spiced their thrusters :-)
> 
> SpaceX is having trouble with helium leaks too. Helium is the chemical
> equivalent of slippery eels. It will leak though almost anything, even
> solid metals. If they need an inert gas, why don't they use argon or
> neon or nitrogen?

Argon and neon aren't all that inert, nitrogen even less so. For 
thrusters, helium's low molecular weight is a real advantage. Hydrogen 
would be about the same, but it is anything but inert, and leaks almost 
as fast a helium, and atomic hydrogen can produce hydrogen embrittlement.

https://en.wikipedia.org/wiki/Hydrogen_embrittlement

-- 
Bill Sloman, Sydney