#garfield Logs

Nov 08 2015

00:18 katsmeow-afk unevened
00:19 zhanx Murphys law was a monkey on my back today
00:19 katsmeow-afk JL wants you in #seastead,, something about irc and phones
00:20 zhanx K
01:04 rue_shop3 ok I think I'm working out this power supply
01:06 rue_shop3 ok, so, I'm gonna break this in 3 places
01:06 rue_shop3 the dac and conditioning
01:06 rue_shop3 the error amps with voltage scale
01:06 rue_shop3 and the output amp
01:08 katsmeow-afk i wonder if putting my hair up with zip ties is like screaming "i'm a nerd" too loudly
01:48 zhanx And?
01:50 katsmeow-afk "this is the copilot speaking, we will be landing in Austria in one hour" "Umm, this is your passenger speaking, i chartered this jet for Australia....."
02:05 zhanx I wish I come charter a jet
02:12 katsmeow-afk rue, you think a 48v-per-step squarewave is ok?
02:12 katsmeow-afk zhanx , you pm'd me after i was in bed yesterday, what did you want?
02:14 zhanx I figured it out hardware issue
02:31 rue_shop3 katsmeow-afk, for which?
02:33 katsmeow-afk for making 120vac from dc
02:34 rue_shop3 modified sine?
02:35 tsmeow-afk
02:35 katsmeow-afk 0v...48v....96v.... 160v... 96v... 48v....0v
02:36 rue_shop3 hmm
02:36 rue_shop3 I suppose
02:36 katsmeow-afk oops, i left out the 144
02:36 katsmeow-afk it's all variable depening on load and charge anyhow
02:38 rue_shop3 http://www.tubecad.com/2011/10/28/V-to-V%20Amplifier%204.png
02:38 rue_shop3 but but but
02:39 katsmeow-afk Digital Voltmeter Ammeter Ohmmeter Multimeter Volt AC DC Tester Meter US Seller
02:39 katsmeow-afk ( 271496690158 )
02:39 katsmeow-afk nubeestore24414
02:39 katsmeow-afk Feedback percentage of
02:39 katsmeow-afk 99.4%
02:39 katsmeow-afk Over 14000 sold
02:41 katsmeow-afk did they build and test that +/- 60v thing?
02:43 katsmeow-afk because seems to me at 10:1 gain, 6v in will try to make 60v out, but the - on the opamp will be at +44v while the input pin will be at +6 , and it will pop
02:43 rue_shop3 I need an op-amp to have a votlage gain of 12, and I cant get it to do it without oscillating
02:43 katsmeow-afk if it is osc then it's 1) not a good opamp, 2) you didn't bypass the pwr pins with caps
02:44 rue_shop3 power is ok
02:44 rue_shop3 if I go thru 4 transistors to the feedback network, its not happy
02:45 katsmeow-afk umm, right, you'll haveto drop the hf gain somewhere
02:45 katsmeow-afk 4 transistors is prolly too much phase lag
02:46 katsmeow-afk use faster transistors, or add some pf caps to kill the hf responce
02:46 katsmeow-afk or, rembe a transistor
02:46 katsmeow-afk remove
02:47 rue_shop3 and its mightnite here, so your up waaay too late :)
02:47 katsmeow-afk very
02:47 rue_shop3 http://i.stack.imgur.com/zkHwG.gif
02:48 katsmeow-afk no wonder it's oscillating
02:48 rue_shop3 thats prettymuch what I tried
02:48 katsmeow-afk replace C1 with a resistor, shit
02:48 katsmeow-afk c2
02:48 rue_shop3 bring down the immediate gain a little?
02:49 katsmeow-afk bring down?? hell it has infinite dc gain!
02:50 katsmeow-afk the Q1-Q2 combo has more gain than the opamp has!
02:50 rue_shop3 hmm
02:51 katsmeow-afk put a resistor in the Q2 collector line, and a tiny cap across the R1
02:51 katsmeow-afk replace C2 with a resistor
02:52 rue_shop3 yea, the collector, huh
02:52 katsmeow-afk most people wold put a resistor tweent he opamp and Q1-B too, and even a pf cap from Q1-b to gnd
02:53 rue_shop3 ok I'm falling asleep
02:53 rue_shop3 I wanted to play for a while tonight
02:53 rue_shop3 my eyes randomly closing wont help
02:54 katsmeow-afk jigger the values so at max load max voltage out, the opamp is at the top of it's availabe output
02:54 katsmeow-afk 62 for R4 sounds low
02:54 katsmeow-afk i am not going to do the math tho
02:54 katsmeow-afk i am passing out too, gnites
02:55 katsmeow-afk http://i.stack.imgur.com/zkHwG.gif is an ok design cept for the C2 and the lack of hf-killer-caps
02:55 katsmeow-afk zzzzzzzzzzzzzzz
12:28 rue_bed http://www.multixmedia.org/cammill/
13:31 katsmeow-afk does me no good, no cnc, my couplers were pink
16:43 rue_house ok, back from shopping
16:43 rue_house truck is at auto shop
16:44 Tom_itx again!!!
16:45 rue_house nope
16:45 rue_house first time in a year or two
16:45 Tom_itx starter?
16:45 rue_house I put 3 shims in the starter and it still sounds bad, so I put in on the list of things for them to check out for me
16:46 rue_house oil change, lube, etc
16:46 rue_house change coolant
16:46 rue_house the shop I had fix the brake line did an awefull job of it, its just slopping around under the truck
16:46 rue_house few turns around the parking brake cable
16:46 Tom_itx don't go there again
16:46 rue_house na
16:47 rue_house its a tire+ shop, they are good at tires.
16:47 rue_house timing check
16:47 rue_house oh, I should see if I have a light, I dont think I do
16:49 Tom_itx shouldn't change
16:49 Tom_itx it's electronic ignition
16:49 Tom_itx unless you been screwing with it
16:49 rue_house right, but after I did the pickup coil, the shop I took it to said they couldn't check it cause it was electronic
16:49 rue_house aka "we dont know how"
16:50 Tom_itx do you know where it's supposed to be?
16:50 Tom_itx i got a light..
16:50 rue_house on the mark, but I dont think I have a light
16:50 rue_house I might have picked one up this summer at a garage sale, I'll check
23:15 rue_house http://www.tuxgraphics.org/common/images2/article07071/article_voltageamplifier.png
23:15 rue_house huh
23:15 rue_house why is R10 going there?
23:19 katsmeow-afk i dunno
23:20 katsmeow-afk oh, that's your gain
23:21 katsmeow-afk so Q4-C can pull way higher than Q3-E will go
23:21 katsmeow-afk but R10 is your dc feedback to the Q3-E
23:22 katsmeow-afk cute
23:22 katsmeow-afk think of Q3 as an opamp
23:22 katsmeow-afk the emitter is the (-) input , the base is (+) input, the collector is the output
23:25 katsmeow-afk i would still use an opamp, and get my feedback off the output terminals
23:52 zhanx Evening
23:54 katsmeow-afk evening
23:54 zhanx Question, my 400 watt convert blew a mosfet? (Look like a power regulator ) is that common?
23:55 katsmeow-afk only if it lost the fan and oveheated, or you had an engine charging the batery it was running off of
23:55 katsmeow-afk else, it shuld have shut off before self-destructing
23:55 katsmeow-afk but wtf do i kow?
23:56 zhanx Not sure what I know either
23:57 katsmeow-afk power regulators look like TO-92, TO18, TO220, TO218, TO126, TO3 , so do mosfets
23:58 zhanx It was on the ac side of the circuit