#garfield Logs
May 18 2020
#garfield Calendar
02:03 AM rue_mohr: zh...
02:09 AM rue_mohr: https://twitter.com/ComradeRobot/status/1253906681353789446
03:04 AM * polprog is enetring runlevel 5
03:05 AM polprog: i have some Sun junk cards, i should take a closer look at what's on them
03:18 AM rue_shop2: ... are you awake already?
03:18 AM polprog: already? it's 10:00
03:18 AM rue_shop2: ugh 1am
03:18 AM polprog: i should be awake since 8:00
03:18 AM rue_shop2: you dont sleep 8 hours?
03:19 AM polprog: i do
03:19 AM rue_shop2: oh dear
03:19 AM polprog: i went to sleep at like.. 2:00 local
03:19 AM rue_shop2: how long I been at this
03:19 AM polprog: pretty long
03:19 AM polprog: i shouldnt have stayed up that long
03:19 AM polprog: hey
03:19 AM polprog: great job on that intensity graded VFD!
03:19 AM rue_shop2: :)
03:20 AM rue_shop2: I love how the E worked out
03:20 AM polprog: yeah
03:20 AM polprog: i have 3 identical displays, similar to yours
03:20 AM polprog: from a calculator
03:20 AM rue_shop2: I was already going to use the M for memory
03:20 AM rue_shop2: yep
03:20 AM polprog: maybe i should put them together and make a funny display
03:20 AM rue_shop2: :)
03:22 AM polprog: maybe try making it a graphic display..
03:27 AM rue_shop2: Tom_L, at some point you need to try out cnc milling pcb's and set up a process, tell me how :)
03:31 AM rue_shop2: oh I'm hearing voices, time to get to bed
03:38 AM polprog: what do they say?
03:38 AM rue_mohr: its mumbly chitchat
03:38 AM polprog: try joining them
03:39 AM rue_mohr: its a tail end of my mental state before I drift off to sleep
03:40 AM polprog: ever fell to sleep in the workshop?
03:40 AM polprog: s/to sleep/asleep/
03:41 AM rue_mohr: nodded off a few times in the chair
03:41 AM rue_mohr: wake up half numb
03:42 AM polprog: so the compaq evo box is now on the other office chair
03:42 AM polprog: there is no spac for it.. its useful (i have to reinstall debian, on it cos the packet structure is fubar)
03:42 AM polprog: space*
03:42 AM rue_mohr: ah, an evil
03:43 AM rue_mohr: I used to have a bunch of them
03:43 AM polprog: i end up moving it between the chair and the bed
03:44 AM polprog: they are very nice
03:44 AM polprog: it was.. probably my first PC
03:44 AM polprog: it was a family PC but i was mostly using it
03:52 AM rue_mohr: ok, what was the last project I put the encoderswitch on
03:52 AM rue_mohr: freq gen?
03:52 AM polprog: probably
03:53 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1100671.jpg
03:53 AM rue_mohr: hehe
03:53 AM polprog: whats that?
03:53 AM rue_mohr: the freq gen
03:53 AM rue_mohr: its a 7490
03:53 AM rue_mohr: I made them into SIP modules for /10
03:54 AM polprog: nice
03:55 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1110360.jpg
03:55 AM rue_mohr: aha, thats a debounce filter module
03:56 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1110438.jpg
03:56 AM rue_mohr: the top left chip is the 7414 used as debounce
03:56 AM rue_mohr: I wonder if I should just do that again
03:56 AM rue_mohr: it was easy
03:57 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1110472.jpg
03:58 AM polprog: i dont have the pics of that compaq board on the server
03:58 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1110473.jpg
03:58 AM rue_mohr: the switch just needs wires off it
03:58 AM polprog: https://twitter.com/polprogpl/status/1260222026909986818
03:58 AM polprog: they are in this thread
03:58 AM rue_mohr: ah, heh yea
03:59 AM rue_mohr: oh yea, the evos are the ones that trip all the caps...
03:59 AM polprog: https://polprog.net/rozne1/ircjunk/computers/compaq_remoteaccess.jpg
03:59 AM polprog: https://polprog.net/rozne1/ircjunk/computers/compaq_remoteaccess_daughter.jpg
04:00 AM polprog: i was to repair these
04:00 AM rue_mohr: http://ruemohr.org/~ircjunk/projects/freqGen/p1110505.jpg the output on that freq gen was nasty
04:00 AM rue_mohr: and its only 10Mhz
04:04 AM rue_mohr: oooh
04:04 AM rue_mohr: maybe I'll etch boards for the resistor module carriers, I can make it fit pots
04:05 AM rue_mohr: that would shave a few days off sorting thru resistors
04:07 AM rue_mohr: oh goodie!
04:09 AM polprog: what's T F.F?
04:10 AM polprog: the caps on mine look sokay i think
04:10 AM polprog: okay*
04:11 AM rue_mohr: Toggle Flip Flop
04:11 AM polprog: ah
04:12 AM rue_mohr: I dont know what I was up to
04:12 AM polprog: now? you were looking for a project that was using a rotary encoder
04:12 AM rue_mohr: hah no
04:12 AM rue_mohr: in the TFF diagram
04:12 AM polprog: there is a VFD display and an iron here
04:19 AM rue_mohr: :) the power supply is the hard part
04:19 AM rue_mohr: unless you have a mains transformer that was designed for it
04:19 AM rue_mohr: then its easy
04:20 AM polprog: i think ill try making a relaxation oscillator from an ULN2003
04:20 AM rue_mohr: the trap is that a relaxation osc cant reliably do 50% duty
04:21 AM rue_mohr: for a pushpull transformer, you need to be *right* on 50%
04:21 AM rue_mohr: there is nothing to say you *have* to use a pushpull
04:21 AM rue_mohr: if your flyback, you have to add regulation
04:22 AM polprog: i was thinking i could use 1 stage of 2003 for the relaxation, and the remaining 6 for a charge pump
04:22 AM rue_mohr: ok
04:22 AM rue_mohr: a few designs seem to use charge pumps
04:22 AM polprog: or 1 for relax, 1 for buck converter and the remaining for a charge pump
04:23 AM rue_mohr: you can also make 2 gates into a toggle flipflop
04:23 AM polprog: ring oscillator uses 3 stages, so in theory there could be 4 stages of pump
04:23 AM polprog: it would be nice to have it all on a single IC
04:23 AM rue_mohr: yep
04:23 AM rue_mohr: 4047 :)
04:24 AM polprog: no, single uln2003 :P
04:24 AM rue_mohr: :) yup
04:24 AM rue_mohr: https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/waveforms-tim17.gif
04:24 AM rue_mohr: that is a T flipflop
04:24 AM rue_mohr: the transistors can be ULN2003
04:25 AM polprog: ah, right
04:25 AM polprog: heh
04:25 AM rue_mohr: the 3.9k resistors can be either half of a pushpull transformer ;)
04:25 AM rue_mohr: and it can be driven by a 3rd gate with a relaxation osc config
04:25 AM rue_mohr: or a phase delay
04:26 AM rue_mohr: its a lot of external parts, so I dont think I tried it
04:26 AM polprog: yeah
04:26 AM rue_mohr: a TL494 should replace all of it BUT
04:26 AM polprog: ill try the relaxation osc
04:26 AM rue_mohr: the tl494 can barely go up to 50Khz and can only drive 250ma
04:26 AM rue_mohr: (fine print sucks)
04:27 AM rue_mohr: tl494 = KA7500
04:27 AM rue_mohr: yea, you probably have some
04:27 AM rue_mohr: :) I'v now overloaded you with options
04:27 AM polprog: damn you again
04:27 AM polprog: :)
04:29 AM rue_mohr: bbl -> sleep
04:29 AM polprog: see you around
12:40 PM rue_bed: and done
12:40 PM rue_bed: you finished obligated tasks yet?
12:40 PM rue_bed: where is z?
12:45 PM Tom_L: before y
01:37 PM rue_mohr: ok I need breakfast
01:37 PM rue_mohr: and I have some boards to etch
01:38 PM rue_mohr: did I write down all my ideas?
02:10 PM polprog: hey rue_mohr
02:10 PM polprog: i got all stuff finished
02:10 PM polprog: and i just built a vfd power supply!
02:10 PM polprog: it works!!!
02:10 PM rue_mohr: :)
02:11 PM rue_mohr: did you select a screen?
02:11 PM polprog: i got filament voltage and anode voltage off single core
02:11 PM polprog: yeahi have some
02:11 PM rue_mohr: how many volts do you have from the supply to drive it?
02:12 PM rue_mohr: ~30?
02:12 PM polprog: anode is about 30 yeah
02:12 PM rue_mohr: my screen, loaded all the way up, pulls 66mA
02:12 PM polprog: its all jumping around
02:12 PM polprog: 37 now
02:12 PM polprog: was 24
02:12 PM rue_mohr: ok
02:12 PM rue_mohr: that should all be ok
02:13 PM rue_mohr: you have a variable bench supply?
02:13 PM polprog: yeah
02:13 PM polprog: the whole thing runs off 5V
02:14 PM polprog: at 230mA
02:14 PM rue_mohr: so, to get the filament voltage, I used a variable bench supply,
02:14 PM rue_mohr: watching it really closely I dialed it up till I *just* saw a glow from the filament, then used a slightly lower votlage
02:14 PM rue_mohr: mine was 4V
02:15 PM polprog: this one is hard to say. the filament is a tap off the original DCDC coil
02:15 PM polprog: ill sketch it up for you in a sec
02:15 PM rue_mohr: the filament needs to be biased up about 5V
02:16 PM rue_mohr: the filament needs to be isolated tho... kinda
02:17 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160196.jpg
02:18 PM rue_mohr: when done like that, any voltage below 5V is off
02:18 PM polprog: hmm
02:18 PM polprog: ok, so far to get it to light up i grounded one end
02:18 PM rue_mohr: the segments drive to ~30V so their on by 25V
02:18 PM polprog: ill rewind it to centertapped
02:18 PM rue_mohr: carefull not to burn up the filament! :)
02:19 PM rue_mohr: the filaments work in LOTS of different modes
02:19 PM rue_mohr: but the best for even illumination is the center tapped winding
02:19 PM rue_mohr: most AC mains ones dont tho
02:19 PM rue_mohr: they do the divider like thing
02:20 PM rue_mohr: I was actaully pondering changing this one
02:20 PM rue_mohr: the right hand digits are a bit dimmer due to phosphor wear
02:20 PM rue_mohr: if I lop-sided the filament, I could kinda compensate it
02:21 PM rue_mohr: so far I'm just ignoring the issue
02:21 PM rue_mohr: my drive voltage is 37-39, its too high, the phosphor directly under the filaments doens't light fully
02:22 PM rue_mohr: I thought the pwm of the scanning would negate the effect
02:23 PM rue_mohr: my screen, fully dialed up, takes about 5w
02:25 PM polprog: how the hell does this work
02:25 PM polprog: you remember
02:26 PM polprog: one of the first DCDCs youve shown me. twomosfets and a center tapped tansformer, mosfets short each ends to ground
02:26 PM polprog: what was the name of it
02:26 PM polprog: im to tired to wrap my head around it
02:31 PM rue_shop1: its a type of transisto bistable
02:31 PM rue_shop1: sounds like...
02:32 PM rue_shop1: https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/waveforms-tim20.gif
02:32 PM rue_shop1: R1 and R4 are the two transofrmer coils
02:33 PM rue_shop1: and the feedback can be done different
02:33 PM rue_shop1: ?
02:34 PM rue_shop1: https://www.electroschematics.com/wp-content/uploads/2012/11/12vdc-120vac-inverter.jpg?resize=527%2C310?w=527
02:34 PM rue_shop1: I think its still a type of royer
02:35 PM polprog: ok, got it drawn
02:35 PM polprog: i count get it around my head cause i thought the coil was wound in a different way
02:35 PM aandrew: oof, went way overboard on the booze last night
02:36 PM aandrew: finally took some ibuprofen at noon
02:36 PM polprog: https://pasteall.org/pic/d84c997905d245c2b51cb30bfca0ba8f
02:36 PM polprog: ibuprofen+booze = baaad
02:36 PM aandrew: polprog: no no I didn't take it with booze
02:36 PM polprog: ikr
02:36 PM polprog: just saying
02:37 PM aandrew: I had a hangover this morning, suffered through it for 4h and then said fuck it and took the pill to zap the hangover
02:37 PM polprog: im always afraid of taking ibuprofen after booze, im know im sober but i cant be sure
02:37 PM rue_shop1: you probably want resistors from the far side of the coil ;)
02:37 PM polprog: waht resistors?
02:37 PM rue_shop1: to the inputs of the gates
02:37 PM rue_shop1: you might need dividers
02:37 PM polprog: hmm
02:37 PM polprog: nah, it works fine..
02:37 PM rue_shop1: the votlage is a bit high
02:37 PM rue_shop1: ok...
02:38 PM polprog: it is short of 40 peaks yes
02:44 PM rue_shop1: the uln2003 max input is upposed to be ~30
02:44 PM rue_shop1: iirc
02:45 PM aandrew: I learn a lot just by keeping my mouth shut and watching
02:46 PM rue_mohr: I was looking at the history last night
02:47 PM rue_mohr: aandrew, you have vfd's with spec sheets!
02:47 PM aandrew: rue_mohr: yes
02:48 PM aandrew: expensive damned devices, but pretty
02:48 PM polprog: i think i have to rewind the filament power to be centertapped
02:48 PM polprog: and have a bit more windings
02:48 PM aandrew: so... about 1V/turn, what is that limit about
02:49 PM aandrew: i.e. why is it not 1mV/turn or 100V/turn
02:49 PM aandrew: what is it about 1V/turn
02:50 PM polprog: probably current capability? im not sure
02:51 PM rue_mohr: .
02:51 PM rue_mohr: hey, would you power up the filament of one to rated V and tell me if you can see it glow at all?
02:52 PM aandrew: um, I have to find them first which might take some doing
02:52 PM rue_mohr: aandrew, core saturation
02:52 PM aandrew: I haven't seen them in... years
02:52 PM rue_mohr: there are two ways to saturate a filament
02:52 PM rue_mohr: (correct me if you know otherwise)
02:52 PM rue_mohr: amp*turns or volt*seconds
02:52 PM aandrew: I do remember the VFD in my old Jeep you *could* see the filament glow but only in absolute dark
02:52 PM aandrew: do you mean saturate a core?
02:53 PM rue_mohr: yea
02:53 PM rue_mohr: flux density
02:53 PM rue_mohr: for all practicallity, flux strength
02:53 PM rue_mohr: for all practicallity magneto-motive force
02:54 PM rue_mohr: so, if you put 1A thru 10 turns, the core sees 10Amp-turn
02:54 PM rue_mohr: if you have 10V*2ms.... ok, bit sketchy on that one, but it saturates
02:55 PM rue_mohr: saturation can be avoided with a larger core
02:55 PM polprog: ok, bbl, time to teach maths
02:55 PM rue_mohr: push-pull supplies are nice, cause the secondary counteracts the flux
02:55 PM aandrew: rue_mohr: so 1V/turn is a limit of a specific core size and material, and not some universal constant
02:55 PM rue_mohr: general ferrite
02:56 PM polprog: rue_mohr: so whats the topologu of that dcdc i made called?
02:56 PM polprog: i dont remember the name
02:56 PM polprog: i remember you showed it to me
02:56 PM rue_mohr: but its assumes things about your operating on-time
02:56 PM aandrew: polprog: Royer?
02:56 PM polprog: and im not sure about the winding order.. the dots
02:56 PM polprog: no, cant be royer, there isnt a control winding
02:56 PM polprog: see pastealllink
02:56 PM polprog: see pasteall link*
02:56 PM rue_mohr: the input winding is the feedback winding
02:57 PM rue_mohr: its a special case where Ni = Nf
02:57 PM polprog: hmm
02:57 PM polprog: ok
02:57 PM polprog: gtg
02:57 PM polprog: ping me if you need something
02:58 PM rue_mohr: aandrew, if your able to test that out, I'd love to know, gives me a ballpark for how to operate the screens
02:58 PM rue_mohr: I also think I'm over on my anode voltage, the beam from the filaments is kinda messed up
02:58 PM rue_mohr: which I'm not worried about
02:59 PM rue_mohr: hoping I dont burn out the phosphor
03:01 PM rue_mohr: ok, I think I need a new batch of etchant
03:01 PM rue_mohr: the cupric chloride isn't working out yet
03:39 PM rue_shop1: ok I fixed the charger on ma's cart
04:13 PM Tom_L: smash it all up. it's all good
04:13 PM Tom_L: err i thought you meant it turned back to crystals... mine did
04:14 PM rue_shop1: yea, mine had, it broke up and dissolved ok
04:14 PM rue_shop1: but I'm gonna do a new mix
04:16 PM polprog: ok, it works way better with a c.t. winding at +vcc
04:16 PM polprog: 12v here
04:31 PM rue_mohr: ....
04:32 PM rue_mohr: you tutoring or back at it?
04:32 PM rue_mohr: :) or going to bed
04:32 PM polprog: back at it
04:33 PM polprog: https://twitter.com/polprogpl/status/1262494349125988360?s=19
04:34 PM rue_mohr: ok
04:34 PM rue_mohr: nice
04:34 PM polprog: shame the agilent screenshots are that big, if only irfan could print the image on the bottom
04:34 PM rue_mohr: looks bright, is it just the camera?
04:34 PM polprog: i could have more space
04:34 PM polprog: the camera
04:34 PM polprog: but it is pretty bright
04:34 PM polprog: the filament is centered around +12
04:35 PM rue_mohr: huh
04:35 PM rue_mohr: not ~5?
04:35 PM rue_mohr: interesting
04:35 PM rue_mohr: how many volts is your filament?
04:35 PM polprog: across?
04:35 PM polprog: or how many till glowing?
04:35 PM rue_mohr: yea
04:36 PM polprog: about 2.5V till glowing
04:37 PM rue_mohr: oo low votlage fil!
04:37 PM polprog: its a tiny display
04:37 PM polprog: the 10x 7 seg was about 3.5
04:37 PM rue_mohr: ok
04:49 PM polprog: with the filament disconnected fromthe secondary the power draw drops from 270 to 60ma
04:49 PM polprog: amazing
04:50 PM rue_shop1: well
04:51 PM rue_shop1: you have 2.5V, can you measure the current? may not easy
04:51 PM rue_shop1: you can give it 2.5V DC and measure the current
04:51 PM polprog: ill just put a shunt across and use the scope
04:54 PM polprog: 3.0V amplitude across 10R
04:54 PM polprog: but thats amplitude
04:54 PM polprog: peak to peak is 3.6V
05:09 PM polprog: https://polprog.net/rozne1/ircjunk/vfd_dcdc/
05:09 PM polprog: more pics
05:17 PM * polprog shakes rue_mohr in a harmonic manner
05:17 PM rue_mohr: oh whats up
05:17 PM rue_mohr: stripping pcb's and etching
05:17 PM polprog: oh, ok
05:18 PM polprog: i could replace these two 1n4148s with a dual diode
05:18 PM rue_mohr: so, your driving your filament with 2.5V
05:18 PM polprog: that would get the part count down to... ULN/two mosfets, dual diode, core
05:18 PM polprog: nice..
05:18 PM rue_mohr: and a 10R has 3V across it...
05:18 PM polprog: no, https://polprog.net/rozne1/ircjunk/vfd_dcdc/IMG_20200518_234759.jpg
05:18 PM polprog: well
05:18 PM rue_mohr: ooo
05:19 PM rue_mohr: thats not the mode I'd expect
05:19 PM polprog: theres a current trace there, voltage across a 10R shunt
05:19 PM polprog: what mode?
05:19 PM rue_mohr: well, I expect those to operate ~50% duty
05:19 PM polprog: ah
05:20 PM polprog: yeah, its weird
05:20 PM rue_mohr: :) it works tho!
05:20 PM polprog: very weird..
05:20 PM polprog: yeah
05:20 PM polprog: probably would take more current with 50% duty
05:20 PM polprog: bear in mind that the scale is 10V/div
05:20 PM polprog: so the ULN may be open for more than you expect
05:21 PM rue_mohr: cool
05:21 PM polprog: if you are talking about https://polprog.net/rozne1/ircjunk/vfd_dcdc/uln_inputs.jpg
05:21 PM rue_mohr: the uln is good for 50V on the output
05:21 PM rue_mohr: but "good for 30V" on the input
05:21 PM rue_mohr: iirc, if it wasn't 8V
05:21 PM polprog: im abusing it a bit.. i think i will replace that with two mosfets
05:21 PM polprog: and see the waveforms
05:22 PM rue_mohr: so whats the sense resistor on the filament current?
05:22 PM polprog: 10R
05:22 PM rue_mohr: but the filament is way less than 10R
05:22 PM rue_mohr: all the voltage would drop in the sense resistor?
05:22 PM polprog: this core here is just a center-tapped winding wound around an existing core
05:22 PM polprog: it got a little dimmer when i hooked up the sense resistor
05:23 PM polprog: i could measure directly across the filament
05:23 PM rue_mohr: to get the current you want a ~1R or 0.1R
05:23 PM polprog: lets see what i have
05:23 PM rue_mohr: then its not messing with the circuits normal operation
05:25 PM polprog: 1.0R...
05:26 PM rue_mohr: k, what voltage does it see?
05:29 PM polprog: 272mA RMS across 1R, 7.3V pk-pk, 1.4V RMS
05:29 PM polprog: voltages are across the filament, current is measured across the 1R
05:32 PM polprog: https://polprog.net/rozne1/ircjunk/vfd_dcdc/PRINT_09-filament_iu.jpg
05:37 PM polprog: interesting.. one of the diodes was not sitting firmly in the breadboard
05:37 PM polprog: replaced them with a dualdiode and the power draw dropped to 150mA
05:59 PM rue_shop1: root@freebee6:/files/Home/plotterspool# ohm -v 3.65 -i 272m
05:59 PM rue_shop1: Power is: 992.800mW
05:59 PM rue_shop1: remember the filament only sees half the p-p ever
06:00 PM polprog: right
06:01 PM polprog: hmm, i just took one of the cores i thought was crap, built a similar topology with p55nf06 instead of uln2003s and i can easily get 11V from 5V converted
06:01 PM polprog: literally wound a pair of 5 turns on it
06:04 PM rue_shop1: nice
06:04 PM rue_shop1: lets see!
06:04 PM polprog: little experiment now
06:04 PM polprog: see what
06:05 PM rue_shop1: push it, see what it'll do!
06:05 PM polprog: ah
06:05 PM rue_shop1: ... use current limiting...
06:05 PM polprog: already took it apart :/ i have a better idea
06:05 PM polprog: i have current limit set to 250mA on the psu..
06:05 PM polprog: and it takes less
06:06 PM rue_shop1: mind, some of the better ideas dont work out as well
06:06 PM polprog: takes 130
06:09 PM rue_shop1: so
06:10 PM rue_shop1: its a pushpull, normally the output in that config is 200%- diode
06:10 PM polprog: hmm
06:10 PM polprog: this is cool
06:10 PM rue_shop1: the fact your getting 30V from 5V means there is deadtime, that makes it work in flyback mode
06:11 PM polprog: thats probably due to the weird mode of uln, theres about 50-60% when both inputs are low
06:11 PM rue_shop1: so your voltage is being limited by *something* be it the filament, or the soft breakdown of something
06:11 PM polprog: what do you mean?
06:11 PM rue_shop1: if it was enough inductance, both inputs might be able to be low and the current wont get high enough to matter
06:11 PM rue_shop1: when one side goes to 0V
06:12 PM rue_shop1: the other side should go up to 24
06:12 PM rue_shop1: er
06:12 PM rue_shop1: sorry your running at 5
06:12 PM rue_shop1: the other side should go up to 10
06:12 PM rue_shop1: then they switch
06:12 PM rue_shop1: at 50% your output should be 10V - diode
06:13 PM rue_shop1: if you "let go" of a coil completely
06:13 PM rue_shop1: it'll do the inductor thing and generate a lot fo voltage
06:13 PM rue_shop1: thats flyback
06:13 PM rue_shop1: if your going 5V in, 30V out
06:13 PM rue_shop1: you have a pushpull flyback
06:13 PM rue_shop1: which is strange, but whatever
06:14 PM polprog: so flyback is when the switch is off
06:14 PM rue_shop1: flyback is when an inductor is left to release its charge at whatever voltage it can
06:14 PM polprog: ok
06:15 PM rue_shop1: the pushpull thing is meant to be output controlled by the fact one side is always being operated
06:15 PM rue_shop1: which means the output is 2Vin
06:15 PM rue_shop1: unless you do like I did and add extra windings to boost it more
06:16 PM polprog: this is interesting: https://polprog.net/rozne1/ircjunk/dcdc/magnetic_coupling.jpg
06:16 PM rue_shop1: the other difference is that pushpull uses the core to conduct the magnetism and does not store anything in the core
06:17 PM rue_shop1: flyback stores all the power in the core and then transfers from there to the ouput
06:17 PM rue_shop1: haha wtf
06:17 PM rue_shop1: creative, technically... doable
06:17 PM polprog: i was thinking yestreday night
06:18 PM rue_shop1: yup, its legel!
06:18 PM rue_shop1: legal
06:18 PM polprog: what if i connected three like that
06:18 PM polprog: but that would be the same as a 3 winding transformer
06:18 PM rue_shop1: possibly not super efficient
06:18 PM polprog: probably has some nice RF mixing applications
06:18 PM polprog: yeah
06:18 PM rue_shop1: :)
06:18 PM polprog: i could probably control a flyback by saturating the core more or less
06:18 PM polprog: i should try that
06:18 PM polprog: argh
06:18 PM polprog: no
06:19 PM rue_shop1: why not
06:19 PM polprog: i should build the VFD power supply as a module first
06:19 PM polprog: lol
06:19 PM polprog: project number -256
06:19 PM rue_shop1: it already operates via saturation
06:19 PM rue_shop1: hahaha
06:19 PM polprog: i mean... if i have a control winding that i use to inject some current.. then the flyback action should be suspressed more or less
06:19 PM polprog: right?
06:20 PM polprog: the more i inject the more it becomes a piece of wire than an inductor
06:20 PM polprog: so it makes it suitable to control the output voltage with an error amp
06:20 PM polprog: its one way of doing that
06:25 PM polprog: they probably used to do logic gates with cores like that
06:25 PM polprog: at some point
06:26 PM rue_shop1: you know that linkis better off at one bit shorted turn, right?
06:26 PM polprog: huh?
06:26 PM polprog: you mean the twist?
06:26 PM rue_shop1: the voltage is just a meter of how fast the flux in the core changed
06:27 PM rue_shop1: yea
06:27 PM rue_shop1: if it was one big copper ring
06:27 PM polprog: oh yeah
06:29 PM polprog: time to grab some food and go to sleep..
06:29 PM polprog: i think ill finally eat the herring
06:29 PM polprog: thats in the kitchen since the morning
06:37 PM polprog: the herring seems to be long gone.. who could have commited such a hideous crime?
06:56 PM Tom_L: wtf has happened here!!!!
06:56 PM Tom_L: this is one of the busier channels
06:58 PM polprog: what?