egg|nomz|egg 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.
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<egg>
!wpn bofh
* Qboid
gives bofh a meowing bifurcation
<UmbralRaptor>
hopf cat
<UmbralRaptor>
!
<UmbralRaptor>
!wpn -add:simaril
<Qboid>
UmbralRaptor: Invalid type
<UmbralRaptor>
!wpn -add:wpn simaril
<Qboid>
UmbralRaptor: Weapon added!
<UmbralRaptor>
!wpn -add:wpn beaker
<Qboid>
UmbralRaptor: Weapon added!
<UmbralRaptor>
!wpn -add:wpn vial
<Qboid>
UmbralRaptor: Weapon added!
<UmbralRaptor>
!wpn -add:wpn flask
<Qboid>
UmbralRaptor: Weapon already added!
<UmbralRaptor>
!wpn -add:wpn tube
<Qboid>
UmbralRaptor: Weapon already added!
<UmbralRaptor>
!wpn -add:wpn phial
<Qboid>
UmbralRaptor: Weapon added!
<UmbralRaptor>
!wpn -add:adj vile
<Qboid>
UmbralRaptor: Adjective added!
<UmbralRaptor>
!wpn
* Qboid
gives UmbralRaptor a pulsed RS-232 field
<soundnfury>
!wpn -add:asj Weierstrass
<Qboid>
soundnfury: Invalid type
<soundnfury>
!wpn -add:adj Weierstrass
<Qboid>
soundnfury: Adjective added!
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<egg>
!wpn -add:adj Weierstraß
<Qboid>
egg: Adjective added!
<egg>
!wpn -remove:adj Weierstrass
<Qboid>
egg: Adjective removed!
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<APlayer>
egg: If I am looking at RKF-Methods, I use the b* constants to compute the actual integral and the difference between the b* and the b-computed integrals to estimate the error? Or how does that work?
<egg>
yeah, you have two integration methods in one (with only one set of coefficients that differs, no need to do the force evaluations twice), they have different orders, so the difference is an error estimate for the lower-order one
<egg>
(you still use the higher-order result, because you have it so it would be silly not to)
<egg>
note that the error estimate needs to be elevated to some well-chosen power
<APlayer>
Humm, so the lower-order integral's s is smaller than the higher one? Because, as far as I can see, Wikipedia just names both of them s
<egg>
... you do realize that if you just throw letters at me without context I have no idea what s refers to, right?
<APlayer>
Alright, sorry
<APlayer>
When you say Y*_n+1 = Y_n + h*sum(b*_i k_i) from i = 1 to s
<egg>
s is the number of stages, not the order
<APlayer>
This s is named s for both, the lower order and the higher order method
<APlayer>
No differences
<APlayer>
Stages as in what?
<egg>
often the lower-order method will have 0s in its last stages
<APlayer>
Alright, so here is my first big misconception: I always thought s = order
<APlayer>
It actually is, up to s = 4 which is the highest I have ever dealt with before
<egg>
yeah but then the butcher barriers get bigger
<egg>
the stages are the k_i
<egg>
the weights are the weights with which you weigh the stages in the sum that gives you the results
<egg>
the nodes are where (in time) you evaluate the right-hand side
<egg>
and the bits in the middle are the Runge-Kutta matrix because nobody came up with a smart name for that
<APlayer>
Humm, s != p clears things up a bit. Though I have basically no idea what you mean in most of your last messages. In particular, I don't know what the "butcher barriers" and the "bits in the middle" are...
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<egg>
the A matrix
<egg>
the stuff in the middle of the Butcher tableau
<egg>
the Runge-Kutta matrix
<egg>
and the butcher barrier is the smallest s you can have for a given p
<egg>
it blows up quickly and is hard to compute iirc
<BPlayer>
And what makes this lower boundary for it to be the smallest s?
<APlayer>
Hi! Ellied, sorry to repeat that question over and over, I should really note it down. In my N-Channel MOSFET, the multimeter should pick up a diode from source to drain, correct?
<APlayer>
And in the P-Channel one too?
<Ellied>
yes
<Ellied>
for both
<APlayer>
Phew
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<BPlayer>
Almost thought I soldered it on the wrong way
<Ellied>
if you blast a hole in the gate and fry it, it will probably just read short (ohmic, no diode) from drain to source. I don't think you'll ever see a diode drop where you aren't supposed to but I'm not sure
<Ellied>
ah except in that case yes
<Ellied>
so the p-channel one should block from source (positive rail) to drain (load) with the gate at the same level as the source
<Ellied>
if theres a diode drop from the terminal you attached to the positive rail (test +) to the terminal attached to the load (test -) , then you have it backwards
<BPlayer>
N-Channel one is ohmic from drain to source
<Ellied>
always? or just when the gate isn't tied to source
<BPlayer>
Have not connected them yet
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<Ellied>
ah, so bridge gate to source with your fingers and try again
<BPlayer>
Seems to stop conducting
<Ellied>
good
<BPlayer>
Uh wait, no
<BPlayer>
Or yes? The reading is sluggish
<Ellied>
sounds like it's fine
<Ellied>
the gate might float around a bit and change the reading but generally it should be an open circuit from drain to source if you connect gate to source
<BPlayer>
There is my problem
<BPlayer>
I was indirectly shorting all three terminals by accidentally touching a diode
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<APlayer>
Huh
<APlayer>
Let me start over
<APlayer>
N-Channel MOSFET, posotive terminal at source, negative one at drain
<APlayer>
Does not conduct
<APlayer>
Linking source and gate drops the resistance to a few MOhm
<APlayer>
Is that correct?
<APlayer>
Uggh, it's the probe, it had a bad contact
<APlayer>
Alright, I am getting diode readings both ways. One is 0.55 V, the other is 1.9x V
<APlayer>
Wait, no
<APlayer>
Man, I get a different reading every time I connect the probes
<APlayer>
It sucks
<APlayer>
BRB, let me get a solid reading first, I will report it when I can confirm it
<APlayer>
OK, so one pin does not conduct anywhere at all. I assume this is the gate.
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<BPlayer>
The other two pins do not conduct one way at all, and I get a diode reading. The other way, they have a resistance of a few MOhm, but connecting the gate to a positive external source does not do anything
<BPlayer>
I think it's dead
<Ellied>
I doubt it, MOSFETs in my experience almost never fail open
<BPlayer>
Then I still have no idea what terminal does what
<BPlayer>
Because the readings are rubbish
<BPlayer>
Once more. One terminal does not conduct to any of the other two, neither one way nor the other. This is the gate.
<BPlayer>
The two other terminals do not conduct one way, but do the other way, with a resistance on the order of 10 - 20 MOhm
<whitequark>
BPlayer: diode reading?
<BPlayer>
Connecting an external +5 V to the gate does nit change the resistance
<BPlayer>
Nor do -5 V change anything
<BPlayer>
whitequark: The multimeters diode mode gives me a 0.58 V or so
<BPlayer>
IIRC that's the correct number for silicon or germanium diodes
<BPlayer>
Ellied: From that, I conclude the MOSFET /is/ dead... Is it not?
<whitequark>
there's a body diode from source to drain
<whitequark>
so, when it conducts, whatever is positive is source
<BPlayer>
Yeah
<whitequark>
how are you checking whether it opens?
<BPlayer>
closes*
<whitequark>
closeS?
<BPlayer>
Attaching an external +5V terminal to the gate
<BPlayer>
And it does not seem to have effect on the other two pins
<whitequark>
why are you saying closes
<BPlayer>
It's an N-Channel MOSFET
<whitequark>
it's an n-channel enhancement-mode mosfet
<BPlayer>
Or am I misunderstanding something again?
<BPlayer>
Gods, this is complicated
<whitequark>
both p-channel and n-channel enhancement mode mosfets are closed with the gate tied to their source
<whitequark>
depletion mode mosfets are open, but they are almost nonexistent
<BPlayer>
It should be an enhancement mode one...
<whitequark>
then you should check for whether it opens
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<whitequark>
connect source to ground, connect drain to +5V via, say, a 10k resistor, check if voltage over the mosfet drops to zero when you pull the gate to +5V as well
<whitequark>
i.e. voltage between source and drain
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<APlayer>
Grr, the internet in the basement works even worse than this MOSFET
<APlayer>
So, again, it should be an enhancement mode MOSFET
<APlayer>
So, let me start over. Is there an idiot-proof way to figure out the pins of an enhancement mode N-Channel MOSFET?
<whitequark>
you're done
<APlayer>
Sorry?
<whitequark>
find the diode. positive lead is source, negative lead is drain, other lead is gate
<whitequark>
you've found the diode.
<whitequark>
also
<whitequark>
19:37 <@whitequark> then you should check for whether it opens
<whitequark>
19:38 <@whitequark> connect source to ground, connect drain to +5V via, say, a 10k resistor, check if voltage over the mosfet drops to zero when you pull
<whitequark>
the gate to +5V as well
<whitequark>
19:38 <@whitequark> i.e. voltage between source and drain
<APlayer>
When I found the diode, do you assume I connected the multimeter in the conductive direction?
<APlayer>
Also, putting a 10 K resistor in there might be difficult. Is it required?
<whitequark>
well if the multimeter shows a diode drop that means you found the diode.
<whitequark>
what do you mean "in there" ?
<APlayer>
Between the gate and the +5V
<APlayer>
s/gate/drain/
<Qboid>
APlayer meant to say: Between the drain and the +5V
<kmath>
<kalium_puceon> Hi can someone recommend a linux terminal emulator that doesn't throw up when it has unicode in it, I registered… https://t.co/NOUuwXxOy2