#garfield Logs

Nov 09 2015

00:23 rue_house katsmeow-afk, I still cant see it, need to redraw
00:24 zhanx Yes
00:24 e_house dosn't feel
00:24 zhanx My back hurts (my fsult)
00:24 rue_house I wuz soakin in the tub
00:25 rue_house ok, R9/Q3/R11 make a normal amp, with no base bias
00:27 rue_house r9 is acting like a BE resistor for Q4
00:28 rue_house R11 will be the input impedence
00:29 rue_house or not
00:29 katsmeow-afk gotta open page again
00:30 katsmeow-afk and it's after midnite so mu bian is of
00:31 rue_house you seem to naturally understand whats up
00:31 rue_house with that
00:31 katsmeow-afk considering the output voltage is not sampled at all, nothing in that circuit is a reliable measurememnt of impedance
00:31 rue_house as the Q3 base voltage goes up
00:31 rue_house the collector goes down, the emitter comes up
00:32 rue_house as the Q3 collector goes down the emitter current of Q4 goes up
00:32 katsmeow-afk Q4-E can't move
00:32 rue_house so the votlage on the C of Q4 goes up
00:33 rue_house (current)
00:33 katsmeow-afk yeas
00:33 rue_house which, causes the voltage of the emitter of Q3 to go up more
00:34 rue_house decreasing its collector current
00:34 rue_house hmm
00:34 katsmeow-afk yeas
00:34 rue_house I still cant see it as a whole
00:34 katsmeow-afk in the mean time the Q4-C pulls the base of Q2 up
00:36 rue_house oh not worried about Q2 and the unlabeled, its just a votlage follower
00:36 katsmeow-afk the actions of Q3 and Q4, and R11 and R10, are designed to keep the current thru Q3 just enough that R9 drops .65v or so, or .7xx
00:36 rue_house emitter follower
00:36 rue_house ah
00:36 katsmeow-afk however, at .7v drop, ot .71v, or .72, Q4 is pulling up a lot, and so Q2 is [uled harder and harder
00:36 rue_house so, R9 is just there as a bias to eat up the BE drop of Q4
00:37 katsmeow-afk yeas
00:37 rue_house ok
00:37 katsmeow-afk gives Q3 something to pull on till it can make Q4 turn on
00:37 rue_house so the base current of Q4 is prettymuch determined by R11
00:37 katsmeow-afk yeas
00:38 rue_house and R10 supplies feedback to prevent the gain from being crazy
00:38 katsmeow-afk yeas
00:38 rue_house ok
00:38 katsmeow-afk but the gain and temperature induced Vdrops of Q2 and Q1 are not in that feedback loop
00:39 rue_house yea
00:39 rue_house I dont need Q1/Q2, I just need a 10x gain that can hit the ground rail
00:39 katsmeow-afk Q1 could use a B-E resistor
00:39 rue_house it dosn't have to hit the + rail cause I can move that up for headroom
00:40 rue_house I dont ahve any op-amps that can take the 36-37V top rail
00:41 rue_house hence this excersize
00:42 katsmeow-afk most audio power amps have an opamp that runs off +/- 15v or so, but thepower amp swings +/- 70v
00:42 rue_house yea, but they are AC and have a bipolar supply
00:42 rue_house I'm DC and have a monopolar supply
00:43 katsmeow-afk should i draw you that circuit again?
00:43 rue_house the one from the page?
00:43 katsmeow-afk i dunno
00:44 rue_house http://www.linuxfocus.org/common/images2/article379/powersupply.gif
00:44 rue_house its a microcontrollered linear supply someone made
00:44 katsmeow-afk holychirt
00:44 katsmeow-afk i didn't
00:44 rue_house you didn't?
00:45 katsmeow-afk no
00:45 katsmeow-afk it's LINUXfocus.org
00:45 katsmeow-afk see C6 thee? that prevents oscillations
00:45 katsmeow-afk pretty big value, actually
00:45 e_house
00:46 katsmeow-afk do yu have a +10 or+15 ?
00:46 rue_house I dont see any other transistor amp like that anywhere
00:46 rue_house I have +36ish, I am subregulating from that
00:46 rue_house I think its 36V, 10A
00:47 katsmeow-afk can you make +15?
00:47 rue_house yea
00:47 e_house waits to hear kats sugges
00:50 katsmeow-afk i drew a dirty pic
00:50 rue_house lets see! lets see!
00:52 rue_house ok so, if your feedback is inverted, you take it to the base of the first transistor, and if its noninverted, you take it to the first transistors emitter
00:55 katsmeow-afk designerthinking.com/DSCF6660m.jpg
00:55 rue_house http://designerthinking.com/DSCF6660m.jpg
00:56 rue_house :) that is a dirty drawing,
00:56 e_house tries to work out what
00:56 rue_house output, e follower,
00:56 rue_house BE resistor...
00:56 rue_house P channel current drive for the last stage... base resistor
00:57 rue_house second to last should have a BE resistor yes?
00:57 katsmeow-afk i missed a BE R on that very top Q, add one there
00:57 rue_house the feedback...opamp...
00:57 rue_house where does the zener ref connect?
00:58 rue_house oh, it raises the level of the first transistor? stepstool?
00:58 katsmeow-afk if the opamp you chose won't turn off thet Q, you can rais the emitter till it does
00:58 rue_house ah yes, I liek to use leds
00:58 rue_house 1.4V
00:59 katsmeow-afk those work fine too
00:59 rue_house ok
00:59 rue_house I will leave this up and make it part of tommorows excersizes
00:59 rue_house your sure you dont ahve too much gain?
01:00 katsmeow-afk ajust resistors to kill off some gain
01:00 rue_house that middle transistor looks like its up for a spotlight
01:00 katsmeow-afk the one from bottom Q-C to top Q-B, for instance
01:00 rue_house hmm
01:00 katsmeow-afk add a C if it oscillates, te normal places
01:01 rue_house I dont need current, just votlage boost, so they could all be pn2222 / 2n3906
01:01 rue_house - to output of op-amp?
01:01 rue_house BE? or is it BC?
01:01 katsmeow-afk umm, aren't those 40v ?
01:01 rue_house 40 is lots more than 36 :)
01:01 rue_house (its a good point)
01:02 katsmeow-afk i'd use 60v or more, you can get up to 300v in a to-92
01:02 rue_house Ihave some 200V's around
01:02 rue_house for an H bridge I was gonna make
01:02 katsmeow-afk the output i (tried) to draw is a darlington
01:02 rue_house middle should be NPN?
01:03 rue_house I dont remember the name for the pair that uses a pnp and npn
01:03 katsmeow-afk opamp - npn - pnp - npn
01:03 katsmeow-afk szliaki
01:03 rue_house that would be why I couldn't remember
01:05 katsmeow-afk https://en.wikipedia.org/wiki/Sziklai_pair
01:06 rue_house it wont help me remember that name
01:06 rue_house :)
01:06 katsmeow-afk ok
01:14 katsmeow-afk the first npn coresponds to your /article_voltageamplifier.png Q3, the top pnp as your Q4 , i combined Q2 and Q1 into a TIP36 or so, and i re-routed R10 for feedback from the output terminals
01:15 katsmeow-afk the curcuit i drew is a classic of high impedance inputs and high power outputs
01:15 katsmeow-afk it has enough gain to throw lots away to make it stable
01:15 katsmeow-afk and teh voltage and current is easily scaleable
01:16 katsmeow-afk and, it's dead simple
01:16 katsmeow-afk there are bells and wistles you could add to it
01:17 rue_bed I'm just shooting for 'works'
01:17 rue_bed it looks like everything so far oscillates badly
01:17 katsmeow-afk it works in so many things it's impossible to make it not works, if built with any common sense
01:18 katsmeow-afk add those C across Q-BE
01:19 katsmeow-afk values depend on the current you set when you choose the R
01:19 e_bed pages thru "IC op-amp cookb
01:19 katsmeow-afk but i'd think .01 are plenty big
01:19 rue_bed the pwm converter only needs from 4 to 7V in, the linear is for testing
01:20 katsmeow-afk don't forget to add the pnp BE resistor i forgot
01:20 rue_bed I keep wondering if I should put all the error control in the digital domain with pulse control
01:20 katsmeow-afk i fogot because i almost put a darlington there, which is why it looks lke i alsmost drew two emitters, and the darlington has a R built in
01:20 rue_bed I'll play tommorow
01:20 rue_bed I have 3 circuits to try now
01:21 katsmeow-afk my curcuit can be stable to 100khz if you need an ultrasonic pwer supply
01:21 rue_bed :)
01:22 rue_bed I'm going for low dv/dt, about 120V/sec or so
01:22 rue_bed for setting anyhow
01:22 katsmeow-afk that's 300ms to turn off from 36v out?
01:22 katsmeow-afk that's rather slow
01:23 rue_bed hmm, ok, maybe a bit faster
01:23 rue_bed tho, I dont think my current supply does much better
01:31 tsmeow-afk waves gn
01:31 katsmeow-afk turning puter off, mning is finished on this puter
20:53 rue_house http://designerthinking.com/DSCF6660m.jpg
20:53 rue_house http://www.ibiblio.org/kuphaldt/electricCircuits/Exper/05243.png
20:53 rue_house http://www.linuxfocus.org/common/images2/article379/powersupply.gif
20:53 rue_house http://www.radio-electronics.com/info/circuits/transistor_2_device_amp/two_transistor_amplifier.php
20:53 rue_house http://myweb.tiscali.co.uk/norcimradiocontrol/Radio15_files/image015.gif
20:54 rue_house http://www.tuxgraphics.org/electronics/200707/bench-power-supply-unit.shtml#0lfindex2
20:56 ^kat^ try a drug to stop that?
20:58 rue_shop3 ?
20:58 rue_shop3 I was transferring the urls
20:58 ^kat^ o
20:58 rue_shop3 just cleared the breadboard
20:59 ^kat^ then ii shold add the R to the schematic
21:04 ^kat^ ok, http://designerthinking.com/DSCF6660m.jpg has the R on Q2
21:05 rue_shop3 ok
21:05 rue_shop3 er, that would be a short, maybe 100k
21:06 ^kat^ i added a short??
21:06 rue_shop3 I was thinking 0k
21:07 rue_shop3 0k is still a resistor...
21:07 ^kat^ i didn't add a short
21:28 rue_shop3 hmm I wonder what a precision, adjustable way to drop 1.25V is...
21:28 rue_shop3 resistor and variable current source?
21:29 ^kat^ if you can make a sink below ground, sure
21:29 Tom_itx couple 3 diodes?
21:29 ^kat^ TL431
21:29 ^kat^ i think it bottoms at 1.25v exactly
21:30 ^kat^ use it like a zener
21:30 ^kat^ nope, 2.5
21:33 Tom_itx rue_shop3, go shine in #robotics a bit
21:33 Tom_itx ehh?
21:33 ^kat^ huh?
21:33 Tom_itx Hi, I'm currently making an Hexapod with 3DOF per legs. It's my first robotic project and I don't know where to start. I understand Inverse Kinematics but I don't know how to make a proper gait. If you have any tips, I will be glad to hear it
21:34 Tom_itx that should be right up his proverbial alley
21:37 rue_shop3 hmm
21:39 rue_shop3 kat, here is an intersting problem
21:39 rue_shop3 ok I have two op-amps going into a diode OR such that each op-amp can push the power supplies output lower
21:39 rue_shop3 one of the amps is used for votlage, the other is used for current
21:40 rue_shop3 the voltage amp gets negitive feedback from the output of the .. well lets say power stage
21:40 rue_shop3 but, what should give feedback to the current amp
21:40 rue_shop3 I suppose, these aren't proper amps
21:40 rue_shop3 they are more like ... followers
21:40 rue_shop3 hmm
21:41 ^kat^ so?
21:41 rue_shop3 well, each error amp should have an input and a feedback
21:41 rue_shop3 that the amp cancels out with
21:42 rue_shop3 but the ref input is direct on the + input
21:42 ^kat^ so?
21:42 rue_shop3 so, its acting more like a comparitor than anything
21:42 rue_shop3 comparitors are partial to oscillating
21:42 ^kat^ what url?
21:43 rue_shop3 tho, on a suggestion from a circuit, I wrapped a parallel 2M and .01uF cap from the op-amps - to the output
21:43 rue_shop3 pulling the gain to about 100
21:43 rue_shop3 didn't post the circuit
21:43 ^kat^ then i cannot comment on it
21:43 rue_shop3 http://ruemohr.org/~ircjunk/projects/newpower/p1070140.jpg
21:43 rue_shop3 hehe
21:44 rue_shop3 http://ruemohr.org/~ircjunk/projects/newpower/p1070122.jpg
21:44 ^kat^ heck
21:44 rue_shop3 its *like* that
21:45 ^kat^ start with a clean sheet of paper
21:45 rue_shop3 :)
21:45 ^kat^ VLC says this song is 1013 hours long, it's been playing for 11 minutes so far........
21:46 rue_shop3 hmm, I get tired of them after about 5 mins
21:47 ^kat^ i wonder if it is n a loop i don't know about
21:47 ^kat^ there's no indicator on the minutes slider
21:47 rue_shop3 I suppose the theme is that there is a votlage regulator, and a current regulator, and whoever wants the output to be lower wins
21:48 rue_shop3 so, as long as I now ignore the votlage section and make it regulate current it'll be ok
21:55 rue_shop3 so if I have an inline resistor, with an isolated current source around it, then I will get a voltage drp
22:00 rue_shop3 cant wrap my head around this
22:00 rue_shop3 if I take a bipolar op-amp
22:00 rue_shop3 I should be able to make it an isolated current source thru a resistor
22:00 rue_shop3 =|>= -\/\/\/- ?
22:01 ^kat^ what??
22:01 rue_shop3 op-amp, with differential outputs
22:02 rue_shop3 resistor 'across' the differential outputs, but with a feedback resisotor to measure current
22:02 ^kat^ youlost me
22:02 rue_shop3 the loop sets the current thru the resistor
22:02 rue_shop3 I need an isolated current thru a resistor
22:03 rue_shop3 hmm
22:16 rue_shop3 I'm going to just go with a difference amplifier
22:29 rue_shop3 ok so
22:29 rue_shop3 if I undarlington it, cause I need no current now
22:30 rue_shop3 and with a 36V supply
22:30 rue_shop3 use a base resistor of 560k
22:30 rue_shop3 and make the opamps output resistor 100k
22:30 ^kat^ damn do they stillmake resistors that high?
22:30 rue_shop3 and use 10k for the other resistors on the npn
22:31 rue_shop3 and use a 10k and 1k to 1:10 the feedback votlage
22:31 ^kat^ 36v / 560k = 6.4ua
22:31 rue_shop3 it looks like the gain will still be insane
22:32 rue_shop3 I did the last output transistor as a pnp
22:32 rue_shop3 so there is 100x gain atleast there
22:32 ^kat^ lil trick: instal tons of gain, shunt it, swamp it, dwarf it with reistors, makes the temperature changes insignificant
22:32 rue_shop3 maybe self-bias the last resistor?
22:33 rue_shop3 BC resistor?
22:33 rue_shop3 I'm really not good at these analog circuits
22:34 ^kat^ i can tell
22:35 rue_shop3 int he time it took you to tell me that other circuit worked like an op-amp I'd started to work out how the first transistor resembled a common emitter amp
22:36 rue_shop3 so then, in your circuit
22:36 rue_shop3 my output rated current is 5mA
22:36 rue_shop3 so, the last transistors base current is (hfe ~100) .05mA
22:37 rue_shop3 50uA
22:37 rue_shop3 how do you suggest I keep the current down that far?
22:37 ^kat^ i wouldn't
22:38 rue_shop3 I dont get it
22:38 ^kat^ you get high enough impedance, and radio stations will be modulating the signal
22:39 ^kat^ or lighting
22:39 ^kat^ or lightning
22:39 rue_shop3 if I have enough (OR lighting) (AND lighting) and (NOT lighting) can I make a lighting half adder?
22:40 ^kat^ yeas!
22:40 rue_shop3 sweet
22:41 rue_shop3 http://www.ibiblio.org/kuphaldt/electricCircuits/Exper/05243.png
22:41 rue_shop3 are you awake enough still to help me remember how the gain works on that?
22:42 ^kat^ no
22:42 ^kat^ but it's ~10 iirc
22:42 rue_shop3 I cant find my "Basic transistor course" book
22:43 rue_shop3 ah, its not an option anyhow
22:43 rue_shop3 comes off the wrong rails, n stuff
22:43 rue_shop3 k, that leaves with yours and the other one
23:15 zhanx Evening
23:35 zhanx Need to make a circle cutting jig tomorrow if I can
23:35 rue_house there is something wrong with me
23:35 zhanx Lime disease
23:36 rue_house maybe, but this gas is insane
23:36 zhanx ?
23:36 zhanx Laughing gas
23:36 rue_house for every 2 breaths I take in, a full breath comes out my ass, its really not fun to be standing over.
23:37 rue_house where is my robotic body?
23:37 zhanx Oh you got intestinal issues
23:37 rue_house I'm going to try to avoid rice for a week
23:37 zhanx Water stool?
23:37 rue_house its one of the only common divisors
23:37 rue_house bad runns yea
23:38 rue_house makes it hard to work 8 hours a day
23:38 zhanx Have your well tested Girardi
23:38 rue_house this situation really isn't much fun
23:38 rue_house say what?
23:38 zhanx Water borne
23:38 ^kat^ ouch
23:39 zhanx You might have some well issues and or a dirty pump allowing for growth of them
23:39 rue_house hmm
23:39 rue_house I wonder if I'v picked up water from somewhere odd
23:40 zhanx Aka boil your drinking water for a week of it goes away that's it
23:40 ^kat^ bear poo in the garden?
23:40 rue_house its a new idea tho
23:40 zhanx 30 minutes roiling boil
23:40 rue_house not that I put there
23:40 rue_house our water is UV treated and chlorinated
23:41 zhanx Or ecoili from the garden thanks to rodents
23:41 rue_house well I suppose I cant rule it out
23:42 zhanx That is actually common
23:42 ^kat^ what do you use the well water from ?
23:42 rue_house I'm getting tired of asking doctors about whats going on
23:42 rue_house the well water is just for the lawn
23:42 zhanx Last idea tapeworm
23:42 rue_house tho some might have gone on the garden
23:42 ^kat^ and the cats rolled on the yard and you pet them
23:43 rue_house no nausea or throwing up tho
23:44 zhanx I saw the rail gun on hackaday.com I want one. Girardi
23:44 rue_house hahha
23:44 rue_house you gonna make one?
23:44 zhanx I might this summer
23:44 rue_house I tried once, the bearing hopped and welded itself to the rail
23:44 zhanx Gonna start collecting capsm
23:44 ^kat^ they usng up all those 12,000ufm 200v caps?
23:45 rue_house it wasn't goin nowhere!
23:45 rue_house geez, my guts are like thunder
23:45 zhanx Girardi classic symptoms and yes I have had it
23:45 rue_house I can hear really large transfers of gas moving around a system not made for it
23:46 zhanx My spicy chili did thst to me also last week
23:46 rue_house hey, the symptoms match
23:47 zhanx Wow
23:48 zhanx Want to know a dumb way in the army we stopped it without meds ?
23:48 rue_house so, i could have picked it up from the cats
23:48 rue_house cannon to intestines?
23:49 zhanx Nope burn a match and eat it
23:49 zhanx After its out of course
23:49 rue_house er, sulfor?
23:49 zhanx Yep
23:49 rue_house or charcoal
23:49 rue_house cause I ahve some medical grade charcoal
23:50 zhanx Might work it was the sulfur we wanted
23:50 rue_house is raw surfor toxic?
23:50 ^kat^ charcoal won't kill cysts, sulfur can
23:50 rue_house how many matches?
23:50 zhanx 2 max a day
23:51 rue_house ... for how many days?
23:51 ^kat^ until the doc gets you something better
23:51 rue_house cysts are growths aren't they?
23:51 zhanx Did one with breakfast amd one at dinner, till it stopped. Normally 3 days max
23:51 rue_house ferever?
23:51 rue_house ah
23:52 rue_house thats gonna take less time than seeing a doctor
23:52 zhanx After thst dehydration became an issue
23:52 rue_house drat, the only surfuric acid I have also contains lead
23:52 rue_house yea, I'v hit bad levels of dehydration 3 times since this started
23:53 rue_house the headache that wont go away
23:53 rue_house cool stuff
23:53 e_house puts matches on the shopping
23:53 e_house notes to NOT substitute ligh
23:53 zhanx And sugar
23:53 ^kat^ sulfuric acid is a diffeent animal
23:54 rue_house its a source or sulfur tho
23:54 zhanx Tablespoon of salt and sugar in 8oz glass is a poor man's iv
23:54 ^kat^ they'd por sulfur on open wounds, you'd pour acid instead?
23:55 rue_house hmm
23:55 rue_house open wound? sulfur? really?
23:55 zhanx Rather pour sugar on an open wound
23:55 rue_house like salt? but I presume more comfortable?
23:55 rue_house wait, your definition of open might be scarry
23:56 ^kat^ like when you can see the bone
23:56 rue_house ok cool I need supper now
23:56 rue_house ughkgchg
23:56 ^kat^ or at least the fat under the skin
23:56 rue_house i got that deep once and freaked out
23:56 rue_house damn sheet metal
23:56 ^kat^ or when you nail your foot to the floor, with your shoes on
23:57 rue_house ok I'm gonna go make supper
23:57 zhanx Sugar has been used since the Roman times to treat battle field wounds fyi