UmbralRaptor changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer. | We can haz pdf
<kmath>
<whitequark> @hikari_no_yume so, the "neutral" wire is tied to the ground (using one of a few common schemes according to code)… https://t.co/hqKxIpL3rn
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<mofh>
egg: I mean even in a TT system the neutral is referenced to an earth *at the generator*. In theory you could still have a fairly high potential wrt local ground against neutral; are neutral-to-TT shorts typically switched on a differential or is it only phase-to-local-earth shorts?
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<egg>
mofh: it's differential, so it compares neutral to phase; I'm not sure what your question is here
<mofh>
egg: oh, derp, you're right. in that case it doesn't matter as much whether you short neutral or phase to ground since either will interrupt current flow.
<mofh>
egg: so really the only difference in a TT system with a differential is that neutral is referenced to ground at the generator or distribution transformer and phase is not.
<egg>
yeah
<egg>
but
<egg>
it's a long way / to the transformer / it's a long way / to ground / it's a long way / to the transformer / ...
<egg>
so neutral might be a quite a bit further off from local earth than in TN-* systems
<galois>
[WIKIPEDIA] Джанибеков, Владимир Александрович#Награды и почётные звания | "Влади́мир Алекса́ндрович Джанибе́ков, урождённый Кры́син (род. 13 мая 1942, посёлок Искандер, Южно-Казахстанская область, Казахская ССР, СССР) — лётчик-космонавт СССР (1978), два
<egg>
whitequark: what's the earthing scheme like in RU
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<egg|laptop|egg>
hm, the ellipsoid of angular momenta such that the kinetic energy has a given value seems to routinely be attributed to Binet or even be called Binet's ellipsoid, but there doesn't seem to be any reference to Binet?
<egg|laptop|egg>
apparently Goldstein calls it the Binet ellipsoid
<egg|laptop|egg>
whitequark: note that we cite [CFSZ07], the preprint, which has some sign errors, because [CFSZ08], the published version, have even more sign errors
<egg|laptop|egg>
s/have/has/
<galois>
egg|laptop|egg meant to say: whitequark: note that we cite [CFSZ07], the preprint, which has some sign errors, because [CFSZ08], the published version, has even more sign errors
<_whitenotifier-cd19>
[Principia] eggrobin labeled pull request #2351: Resolution of Arnold's equation with minimal testing - https://git.io/JeC4j
<SilverFox>
whitequark, how does the commonly known "core clock multiplier" work on a circuit level? is it the crystal running at 100Mhz and some shenanigans are had to literally multiply that across the system, or is it a dope-ass crystal that goes at like, 10Ghz and they just divide the end result to achieve the multiplier?
<whitequark>
former
<whitequark>
the shenanigans are called "PLL"
<whitequark>
the crystal is a frequency *standard*
<whitequark>
you can very easily make a silicon oscillator that goes to like 10 GHz
<whitequark>
unfortunately it will wildly drift with temperature and voltage changes
<whitequark>
so you discipline it with a crystal, basically
<SilverFox>
there's almost always shenanigans
<whitequark>
like you have a counter that counts how many pulses from the silicon oscillator it got during one crystal pulse
<whitequark>
and if it counts low you make the oscillator faster, or if it coutns high you make it slower
<whitequark>
by starving it of voltage or giving it more, usually
<whitequark>
there are other ways too, like multi-tap delay lines
<SilverFox>
fascinating
<whitequark>
but i think voltage starved inverter is commonly used
<SilverFox>
ah, the PLL system uses a VCO
<SilverFox>
and from what I'm reading it does comparator stuff and that alters the voltage to control how the VCO ticks
<whitequark>
that's pretty much what i'm describing
<SilverFox>
"fraction of a hertz" what use cases require precise less than 1 second timing?
<whitequark>
gps
<SilverFox>
alright fair enough
<whitequark>
like
<whitequark>
not gps itself mostly, although that too
<SilverFox>
I understand what you mean yeah
<whitequark>
i mean things like differential gps for agriculture and shit
<SilverFox>
gps as a system wholistically, is very time-dependant
<SilverFox>
and doesnt usually operate faster than 1s intervals
<whitequark>
often does, actually
<SilverFox>
although, wouldn't it be easier to have a crystal that operates at a fixed frequency and just divide it? at least cheaper than having a <1hz controllable oscillator?
<whitequark>
you need fractional-N to get high resolution with a fixed frequency crystal
<whitequark>
it doesn't have to use a PLL
<whitequark>
but i think your resolution is always limited by your crystal