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[02:07:32] <pokmo> hi
[02:08:41] <pokmo> i've got a servo that claims to use a Futaba spline. does futaba use a standard spline?
[02:59:53] <deshipu> I wouldn't bet on it, servo splines are nototiously varying
[03:00:25] <deshipu> even if Futaba has a standard, the clones of their product may use something else
[03:12:57] <pokmo> deshipu: but doesn't Futaba provide a spec for their several splines?
[03:13:26] <pokmo> https://www.servocity.com/html/futaba_servo_splines.html#.V1vB4YRIAZV
[16:41:59] <asdfjb> wrt current flow, many books say + -> -, whereas many others say - -> + (electron flow), which is correct?
[16:42:17] <SpeedEvil> Neither.
[16:42:23] <asdfjb> s/current flow/direction of current flow/
[16:42:24] <SpeedEvil> It's a definitional thing.
[16:42:29] <SpeedEvil> It doesn't matter at all.
[16:42:36] <asdfjb> Elaborate?
[16:42:54] <SpeedEvil> From an electronics point of view, the two are entirely equivalent
[16:43:04] <asdfjb> It seems weird to me, let me give an example
[16:43:53] <asdfjb> - battery + -> resistor -> lamp -> battery -, if you say + to - that makes sense, but if you say - -> + it doesnt because the current would go through the lamp before hitting the resistor
[16:43:53] <SpeedEvil> Pretty much the only case you need to know is if using vacuum tubes, or electrochemical machining.
[16:44:23] <SpeedEvil> Circuits are entirely equivalent whichever way you consider the charge carrier to move.
[16:44:40] <SpeedEvil> And indeed, rearranging the circuit makes no difference at all for series circuits.
[16:45:39] <asdfjb> What about transistors? if you have C B E, does current go from C to E or E to C?
[16:45:55] <SpeedEvil> Which ever way you choose to define it.
[16:46:23] <asdfjb> So it is exactly the same no matter whether its + -> - or - -> +?
[16:46:24] <SpeedEvil> In practice, conventional current - flowing from + to - is probably sensible to adopt simply for convenience.
[16:46:26] <SpeedEvil> yes.
[16:46:50] <asdfjb> So I should read circuit diagrams as + -> -? why do most books use electron flow direction?
[16:46:51] <SpeedEvil> There is no need at all to remember that the electron has a negative charge.
[16:47:17] <SpeedEvil> Some academic books do, because it is from one point of view more correct.
[16:47:38] <SpeedEvil> It is somewhat more important if you're trying to learn semiconductor physics
[16:48:42] <asdfjb> So how does it make sense for example with a circuit: - battery + -> resistor -> lamp -> battery -? if using electron flow, the resistor shouldnt have any impact on the lamp?
[16:49:23] <SpeedEvil> Wrong.
[16:49:51] <SpeedEvil> The charge carrier (whether you consider it + or -) has to flow completely round the circuit in order to complete it.
[16:49:56] <SpeedEvil> This is why it's called a circuit.
[16:50:10] <SpeedEvil> It doesn't matter if it hits the resistor first or last.
[16:50:39] <deshipu> an individual electron actually doesn't travel all the way around
[16:50:50] <deshipu> but the one before it has to move to make room for it
[16:52:06] <SpeedEvil> deshipu: that's just confusing. (true, but confusing)
[16:52:25] <asdfjb> I find it easier to think of circuits as + -> -, is that ok to use? All the component symbols assume + -> -, e.g. diode
[16:53:05] <deshipu> asdfjb: it doesn't matter, really
[16:53:21] <deshipu> whether you look at electrons, or holes for electrons
[16:53:31] <SpeedEvil> asdfjb: yes.
[16:53:59] <SpeedEvil> asdfjb: As an electronic engineer, you never, ever, need to remember which way electrons 'really' flow.
[16:54:14] <SpeedEvil> Pretty much the only exception is if trying to do electroplating or similar.
[16:54:22] <asdfjb> HM
[16:54:24] <deshipu> or vacuum tubes :P
[16:54:24] <asdfjb> *hm
[16:54:36] <SpeedEvil> Or actual semiconductor design.
[16:54:47] <SpeedEvil> But even with vacuum tubes - you just need to read the datasheet.
[16:54:57] <SpeedEvil> Knowing which way the electrons go does not help you at all.
[16:55:17] <SpeedEvil> Just that most vendors stock of p-type tubes is bad.
[16:59:09] <asdfjb> wrt the example above, is + battery - -> resistor -> lamp -> battery + the same?
[16:59:44] <SpeedEvil> You can freely rearrange any component in that series circuit and get precisely the same result
[17:00:38] <asdfjb> Ok, so if I chose to read + -> - I would use the first example, and - > + the example just above
[17:01:29] <deshipu> it's a bit like very densely packed cars on a road
[17:01:38] <deshipu> no matter where a jam is, all the cars slow down
[17:01:54] <deshipu> hmm
[17:02:02] <deshipu> maybe not cars, as they can leave gaps
[17:02:09] <deshipu> maybe train cars
[17:08:46] <SpeedEvil> https://www.youtube.com/watch?v=Sd5ZLJWQmss - this
[17:09:23] <veverak> I need power source
[17:09:26] <veverak> for 5V
[17:09:28] <veverak> 10A
[17:09:30] <veverak> or 50A?
[17:09:32] <veverak> price difference is not so big
[17:09:34] <veverak> :/
[17:11:27] <SpeedEvil> What?
[17:11:45] * SpeedEvil needs a bigger wood-chipper for people who are bad at asking questions.
[17:13:08] <deshipu> SpeedEvil: that wasn't a question
[17:13:40] <deshipu> SpeedEvil: also, wood chippers get clogged easily, get a proper meat grinder
[17:14:10] <SpeedEvil> Not if you also feed the proper amount of wood to ensure rapid composting
[17:14:51] <asdfjb> Thanks for the help
[17:14:58] <deshipu> a friend of a friend used to work at a fox farm
[18:34:09] <kenroy> hello
[18:37:48] <Wetmelon> hello!
[18:40:02] <Wetmelon> Y'all, I need help building a gantry
[18:40:07] <Wetmelon> I know nothing about gantries.
[18:43:42] <SpeedEvil> they're where you get gans from.
[18:44:57] <Wetmelon> I don't get pans from my pantry though
[18:45:05] <Wetmelon> (Is that where that word comes from?)
[18:48:54] <Tom_itx> a gantry crane? a gantry 3d printer, a gantry cnc mill? a gantry what???
[20:21:26] <Wetmelon> Tom_itx: A gantry that can carry a 10lb tool, no sideloading on the tool
[20:21:37] <Wetmelon> At up to say 1500mm/s
[20:25:17] <Wetmelon> I'm thinking just some 4080 + square rails on the X, dual Y rails with the head in between. The biggest ??? is the drive system. Rack & Pinion? Ballscrew?
[20:52:46] <Snert> why, electromagnetoinductionsubnuclear, of course. :)
[21:10:31] <Wetmelon> wat
[21:32:44] <Snert> you know, hamsters :)
[21:56:29] <Wetmelon> Heh
[21:56:44] <Wetmelon> Imma tell my boss that. "Hey, I think we should use ham-hams."