Sujet : Re: OT: EV Charging Stations Stripped of Copper Cables
De : tnp (at) *nospam* invalid.invalid (The Natural Philosopher)
Groupes : uk.d-i-y sci.electronics.designDate : 07. Jul 2024, 14:31:07
Autres entêtes
Organisation : A little, after lunch
Message-ID : <v6e5ar$bi73$1@dont-email.me>
References : 1 2 3 4 5 6 7 8
User-Agent : Mozilla Thunderbird
On 07/07/2024 14:06, john larkin wrote:
We agree that scientists present us with wonderful problems to
instrument but are generally terrible at designing electronics
themselves.
This supposed dichotomy between academic and pragmatic knowledge is false.
Both are necessary
Example 1.
=======
We were developing a laser rangefinder for the Army, featuring fragile optics a ruby laser and a bloody expensive silicon photodiode.
Try as we might we couldnt get more than just over a mile range from the lab roof to a white painted building about a mile away.
One day a boffin with a tweed jacket and pipe came visiting, we explained our problem.
"How much power is the laser?"
"EWhat is te noise figure on the photodiode"?
"I'll see whats what over lunch"
He came back later and sid - "Oh, well its not good news I am afraid, with that much power and that much front end noise you will be lucky to get a mile put of that with a nice reflective target"
So we gave up, drained all the money out that projects budget and cancelled it.
Example 2
======
I was tasked with designing amongst other things a FM Hifi receiver. To save time we imported a Japanese tuner head and I built the IF strip and detector.
The customer was however German, and totally chauvinistic. No Japanese quality. We must have German or at least European, So we got a Philips head.
At once we had massive hiss and hum. I didn't have time to track it diown so a consultant was briught on who spent a fortnight calculating the noise contribution of my IF strop and said 'well it doesn't seem to be that'
'I could have saved to two weeks of calculation'
'How so'
'Just pull the tuner out, put in a 10.7MHz signal into theh IF strip and look! No fucking noise'
(It turned out that wunderbar German tuner head was a pile of crap. They had used a zener diode to stabilize the VCO without seeming to understand that a zener is an ideal noise source, and they had used ferrite slugs in the VCO which make marvellous detectors of magnetic fields. Germans are shit engineers. They make up for it by testing and fiddling till stuff works. A nation of technicians)
The point here is that academic knowledge can eliminate solutions that *cannot* work,. . like 'renewable energy' without having to spend a fortune trying to make it work...
Conversely practical experience is way faster than a computer model...
"Are you sure that beam will take the load of pulling an engine out of t forklift?"
"we pulled a bigger one out with it last week"
-- All political activity makes complete sense once the proposition that all government is basically a self-legalising protection racket, is fully understood.