#garfield Logs
Nov 20 2021
#garfield Calendar
12:29 PM polprog: computers, man
12:37 PM polprog: how are you doing up there? I saw some floods in BC
01:30 PM aandrew: yeah I saw that too, I was flying into Abbotsford, which is apparently built on a giant lake bed
01:37 PM polprog: ouch
01:53 PM rue_mohr: heh just a bit
01:53 PM rue_mohr: I'm ok
01:54 PM rue_mohr: sounds like supplies are going to be a bit thin
01:54 PM rue_mohr: the grocery stores are getting a bit thin, not sure if there is a run or not
01:54 PM rue_mohr: the gas stations are apparently only allowing 30L/purchase
01:54 PM rue_mohr: I NEED A STEAM TRUCK
02:03 PM Tom_L: hydrogen
02:03 PM rue_mohr: no, logs
02:03 PM rue_mohr: we have logs here, we can burn wood
02:04 PM rue_mohr: it was pointed out an engine would be easier to build with some pneumatic cylinders
02:04 PM polprog: my butler oscillator is pretty nonlinear. i think i will build a new one soonish, with attenuation in the feedback
02:04 PM rue_mohr: polprog, harmonics or freq/control
02:05 PM polprog: harmonics
02:05 PM rue_mohr: ah, you just need to tune it
02:05 PM rue_mohr: lets see the circuit
02:05 PM polprog: let me upload it
02:06 PM polprog: i drew it in digikeys eda, i needed it for something
02:07 PM polprog: https://polprog.net/rozne1/ircjunk/uhffun/butler_100mhz.jpg
02:08 PM rue_mohr: ok
02:08 PM rue_mohr: so it wouldn't trim out?
02:08 PM polprog: neither on C2 nor on R2
02:08 PM rue_mohr: c1/c2
02:08 PM rue_mohr: waiut
02:09 PM rue_mohr: what the
02:09 PM polprog: base needs to be biased close to ground to oscillate at all
02:09 PM rue_mohr: wait
02:09 PM Tom_L: do you guys know of a free online circuit simulator that has a vast database of ICs?
02:09 PM Tom_L: asking for somebody...
02:09 PM rue_mohr: no
02:09 PM polprog: LTspice beats it all but its ancient
02:09 PM rue_mohr: you know I dont simulate
02:10 PM rue_mohr: polprog, why is this a class A with a resistor?
02:10 PM Tom_L: nothing quite like the smell of blue smoke in the morning...
02:10 PM rue_mohr: I go thru a LOT of 2N7000
02:10 PM rue_mohr: and PN2222
02:11 PM polprog: It always worked with that resistor, it was my starting point
02:11 PM polprog: for pierce and colpitts
02:12 PM rue_mohr: I'm sure there should be an inductor
02:12 PM rue_mohr: I think between the collector and +
02:12 PM polprog: on the collector?
02:12 PM polprog: hmm, good point
02:13 PM rue_mohr: the other hunch says instead of the 100R
02:13 PM polprog: I dont think you would be able to bias it
02:13 PM polprog: the resistor increases gain linearity
02:14 PM rue_mohr: Xl=
02:15 PM rue_mohr: if you can withstand the loading, the output might be cleaner on the other side of the crystal
02:15 PM rue_mohr: there are hints that you dont need L2
02:16 PM rue_mohr: I think its supposed to be a common-base amplifier
02:16 PM rue_mohr: things generally agree with the emitter using a resistor
02:17 PM rue_mohr: hmm how is a butler different than a collpits
02:18 PM rue_mohr: I think its the crystal
02:19 PM rue_mohr: oh no, my tab count is going up
02:26 PM polprog: eh i think i tried a colpitts with that crystal and i could not get it running at 5th overtone
02:26 PM polprog: the crystal says 100M but its a 20M one, i have to run it in 5th
02:28 PM rue_mohr: wow
02:29 PM rue_mohr: I'm not that good at tuning
02:32 PM polprog: it took me a couple days and phillip's help
02:32 PM polprog: i learnt a lot but i still feel i dont quite get that circuit
02:33 PM rue_mohr: I dont quite think its right
02:34 PM polprog: bottom C and the bottom inductor need to be tuned within ~1 MHz
02:35 PM polprog: or a couple MHz, i dont remember what span i had on the spectrum analyzer
02:35 PM polprog: but it looks cool. You turn the trimmer and the peak goes left and right
02:36 PM polprog: and if you get close enough then the peak just jumps into position and there is a range of the cap where it does not affect the f
02:36 PM polprog: turn it too much and it jumps back out
02:36 PM rue_mohr: http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/5th_order_Overtone_X-tal_LO.gif
02:36 PM rue_mohr: see
02:37 PM rue_mohr: collector
02:37 PM rue_mohr: I'm seeing it on most circuits
02:37 PM polprog: hmm
02:37 PM polprog: ill try to build the next one with an RFC in the collector
02:38 PM rue_mohr: freaking google and their inline images
02:38 PM rue_mohr: there are other exampels I cant quite post
02:38 PM rue_mohr: oh maybe if...
02:38 PM polprog: screenshot
02:40 PM rue_mohr: hold on...
02:40 PM rue_mohr: its more complex thant hat
02:41 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/Buttler_Overtone_Crystal_Oscillator.png
02:41 PM rue_mohr: dafgkjasdfkl;j
02:41 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/Buttler_Overtone_Crystal_Oscillator.png
02:41 PM rue_mohr: funny thing tho, I think its actually a gif
02:41 PM rue_mohr: with .png
02:42 PM rue_mohr: so many freaking software layers that everything just gets shoved thru the same hole anyhow
02:42 PM polprog: heh
02:42 PM polprog: youd thin
02:42 PM rue_mohr: I should make my autopost scripts a bit more flexible
02:42 PM polprog: think
02:42 PM polprog: DOCSIS is putting IP data in MPEG-2 frames. for real
02:43 PM rue_mohr: ...
02:43 PM rue_mohr: wow
02:43 PM polprog: (ok theres BPI in between which does per subscriber encryption)
02:43 PM polprog: [but not on older versions]
02:43 PM rue_mohr: I have to eat and ...drive
02:43 PM rue_mohr: I dont want to drive, fuel is stupid right now
02:45 PM polprog: doesnt say what L1 is
02:45 PM rue_mohr: just see the general layout tho
02:45 PM polprog: i have to rip out some adjustable Ls from something
02:45 PM polprog: yeah
02:45 PM rue_mohr: all the L and C values will depend on your freq
02:45 PM polprog: quite often you cant Just Take the circuit
02:45 PM rue_mohr: no
02:45 PM rue_mohr: rarely do they ever work
02:46 PM rue_mohr: https://gusbertianalog.com/content/images/2021/06/osc.jpg
02:46 PM rue_mohr: I trust images like that waaaay over anything done in cad
02:46 PM polprog: kinda
02:46 PM polprog: but then. damn, everything is upside down
02:46 PM rue_mohr: even tho that ones missing a bunch of detail
02:46 PM rue_mohr: https://www.ourpcb.com/wp-content/uploads/2021/10/3-2.jpg
02:47 PM rue_mohr: I want to give this a try
02:47 PM rue_mohr: but I'll change it to self-biased
02:47 PM rue_mohr: I dont like fixed bias
02:49 PM polprog: i dont trust self biased
02:49 PM polprog: goes haywire with temperature
02:50 PM rue_mohr: hmmm
02:51 PM rue_mohr: it should be the other way around...
02:52 PM rue_mohr: self bias should keep the collector votlage stable as a fn of the BE voltage and gain... ?
02:52 PM polprog: i think both of these values change
02:52 PM polprog: it would make an interesting experiment
02:53 PM rue_mohr: 1 sec
02:56 PM rue_mohr: I thought the book I had said
02:57 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210810.jpg
02:58 PM rue_mohr: I was sure it said that self bias was preffered due to it being more stable
02:59 PM polprog: strange
02:59 PM rue_mohr: their "fixed bias" is just a pullup tho, its not a divider
03:01 PM polprog: ting experiment
03:01 PM polprog: 21:38 < rue_mohr> 1 sec
03:01 PM polprog: pp[s
03:01 PM polprog: oops
03:01 PM polprog: mispaste
03:01 PM polprog: thats self bias tho
03:01 PM rue_mohr: hu?
03:02 PM rue_mohr: a pullup is fixed bias
03:02 PM rue_mohr: did they tell us different stories?
03:03 PM rue_mohr: did you see that oscillator I posted a bit ago, I had to bias it with a diode
03:05 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210672.jpg
03:05 PM polprog: divider between vcc and vee is fixed for me
03:05 PM polprog: just one resistor is self bias
03:05 PM rue_mohr: so
03:05 PM polprog: clever
03:08 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210811.jpg
03:08 PM rue_mohr: so, ABC name the bias...
03:10 PM rue_mohr: well?
03:10 PM rue_mohr: my answer is fixed, fixed, self
03:11 PM polprog: ok
03:11 PM polprog: makes sense
03:11 PM polprog: i forgot that A and C are fundamentally different
03:11 PM rue_mohr: ok
03:11 PM rue_mohr: had me worried :)
03:11 PM rue_mohr: I'm all self-taught
03:13 PM rue_mohr: ok I have to go do things ;(
03:13 PM polprog: have fun
03:13 PM rue_mohr: I dont want to go
03:13 PM rue_mohr: I dont want to leave home and I dont want to dive
03:13 PM rue_mohr: drive
03:14 PM polprog: :/
03:23 PM polprog: bbl
05:46 PM rue_mohr: my body does not want to do things
05:46 PM rue_mohr: I got the bands for the bot tho
05:47 PM polprog: im testing a lithium pack
05:50 PM rue_mohr: k
05:50 PM rue_mohr: Ah?
05:56 PM polprog: mAh
05:56 PM rue_mohr: sute
05:56 PM rue_mohr: sure
05:56 PM polprog: i pulled that particular one from a palm pilot
05:56 PM rue_mohr: fixed current load?
05:56 PM polprog: I have some new 18650s
05:56 PM rue_mohr: voltage cutoff?
05:57 PM polprog: no, i want to check if it has a voltage cutoff. Probably yes cause it had 0.00V across before I charged it
05:57 PM polprog: i put a 270R across it, gonna measure the voltage in 2 min
05:59 PM polprog: started at 0:40 with 3.33V
05:59 PM polprog: 0:44 3.25V
05:59 PM polprog: its two cells
05:59 PM polprog: i have no idea which lithium tech it is
06:01 PM polprog: no idea if its lithium at all :v
06:08 PM polprog: 0:54 3.31V
06:09 PM polprog: stable voltage
06:09 PM polprog: 15 mins at I=U/R
06:09 PM polprog: 12mA * 15min
06:10 PM polprog: ~= 3mAh
06:10 PM polprog: eh
06:10 PM polprog: that gonna take some time lol
06:10 PM polprog: screw that
06:10 PM polprog: its not dead
06:10 PM polprog: at least
06:10 PM polprog: i need to build a source measure unit
06:11 PM polprog: i like this cell because its slim and flat, if it turns out to be working id be happy
06:11 PM polprog: paving my way into portable electronics
06:11 PM polprog: 18650s are universal but they are large
07:13 PM rue_shop3: I made a constant current load
07:14 PM rue_shop3: its sitting here now
07:14 PM rue_shop3: I been meaning to do a 12V battery I have here
07:14 PM rue_shop3: but I was having an issue with oscillation last time I set it up, not sure why
07:14 PM rue_shop3: it would benifit from a case
07:14 PM Tom_L: shower surround in. i'm pooped
07:15 PM rue_shop3: I havn't even done anythng yet
07:15 PM rue_shop3: and I'm feeling done
07:15 PM rue_shop3: well I made some hangers for a guy
07:15 PM Tom_L: i'll be up later. nap time
07:15 PM rue_shop3: but it was just a bit of cutting out some wood
07:17 PM Tom_L: show me how to make pulleys
07:22 PM polprog: i have a constant current load too
07:23 PM polprog: not sure if it will work wit voltages as loow
07:23 PM polprog: i should rebuild it on these 3.3V vgsth mosftes
07:23 PM polprog: mosfets
07:23 PM polprog: im going to sleep