#garfield Logs

Apr 12 2015

03:15 rue_house atom sbc
04:17 rue_shop3 kat, the nerve, one of my fet drivers failed
06:52 katsmeow-afk .
07:06 katsmeow-afk rue, which driver? the descrete one using audio amplifier, or the "mosfet driver chip" one?
07:20 tsmeow-afk looks for some
07:47 tsmeow-afk wonders if rue would have more energy if he had a breakfast and lunch which allowed for 1/2 cc of "lite salt" (1/2 sodium chloride and 1/2 potassium chloride) in each
07:48 katsmeow-afk rue, which driver? the descrete one using audio amplifier, or the "mosfet driver chip" one?
08:23 rue_shop3 the one I did with some transistors
08:24 katsmeow-afk no audio amp?
08:24 katsmeow-afk why did it break?
08:24 rue_shop3 one transistor for open collectorness, and one for a hv amp
08:24 rue_shop3 thats a good question, its intermittently outputting a low of 5.6V
08:24 rue_shop3 fet dosnt like that
08:24 katsmeow-afk not low enough, i think
08:25 katsmeow-afk driving that gate capacitor thru the whole high voltage pulldown is prolly outside the transistor's soa
08:26 tsmeow-afk suggests a inductance in that pulldown if that is the
08:28 rue_shop3 its a transistor pulldown a pullup resistor
08:28 katsmeow-afk this is the maddening part of mosfets: driving amps of current thru at least 10 volts of range
08:29 katsmeow-afk yeas,, see if you can scope that pulldown current
08:29 katsmeow-afk compare to the transistor chart
08:31 rue_shop3 its only about a 2hz signal
08:31 katsmeow-afk i don't care
08:32 katsmeow-afk the sharp edge of the pulldown switch is what is mattering
08:33 katsmeow-afk maybe if you just slow it down, make it a slope, by editing the transistor base drive
08:35 rue_shop3 I was seeing some ringing, I suspect my bipolar driving could use help
08:35 katsmeow-afk you are driving that base with a 74S ? try a 74HC or 74LVC
08:35 rue_shop3 an arduino,
08:35 katsmeow-afk or even a 40xx
08:35 rue_shop3 arduino output to 1k pulldown
08:35 rue_shop3 series 1k from that to base of first
08:35 rue_shop3 emitter of first on ground
08:35 katsmeow-afk ok, insert a RC to slow the signal to the base
08:36 rue_shop3 pullup on collector to ..... something dosn't add up here
08:36 rue_shop3 whats my second transistor for
08:36 rue_shop3 maybe the first ones an inverter?
08:36 rue_shop3 its 6am
08:36 katsmeow-afk iirc, you used a collector pullup to shut off the fet
08:37 katsmeow-afk i had suggested a totem-pole driver
08:37 katsmeow-afk with the totem pole, the pulldown isn't needing to pull the pullup resistor also
08:38 rue_shop3 making it into a 4 pin sip was being a challange
08:38 katsmeow-afk umm, true
08:38 rue_shop3 after I made them, I worked out the lm386 worked better
08:38 rue_shop3 and I have a note to that effect on the slip with the pinout in the bag of them I made
08:39 rue_shop3 I bought like 100 lm386 for use as fet drivers
08:39 tsmeow-afk admires the use of so many prepositions in one short sent
08:40 rue_shop3 I'm astounded I can even form sentences right now
08:40 katsmeow-afk you must need to drive alot of fets?
08:40 rue_shop3 am I still legible or do I just think I am?
08:40 rue_shop3 katsmeow-afk, I wanted an off the shelf solution
08:40 katsmeow-afk you are legible!
08:40 rue_shop3 my shelvs prefable
08:40 rue_shop3 y
08:40 katsmeow-afk 386 is off the shelf
08:40 rue_shop3 tis now!
08:41 katsmeow-afk now, you have 386 ON the shelf too!
08:41 katsmeow-afk and mabe even ON 386's on the shelf
08:41 katsmeow-afk ON Semi
08:45 katsmeow-afk i remembe early opamps were so fragile
08:47 katsmeow-afk you could pop them from not enough bypassing, too fast of an input, preading the inputs to far apart with voltage, bring the inputs too close to Vcc or Vee, too much load, too much heat, using unsych'd Vcc/Vee power cycling, etc etc etc, there were so many ways to kill them
08:48 katsmeow-afk those early opamps is why you see "tracking power supplies" on ebay
08:48 katsmeow-afk iternets say it's still 52f outside
08:56 katsmeow-afk tv too
09:02 katsmeow-afk Documents/_ chips/LME49810 - 200V Audio Power Amplifier Driver with Baker Clamp.htm
09:03 katsmeow-afk THD+N (f = 1kHz) 0.0007 (typ)
09:03 katsmeow-afk Slew Rate 50V/�s (typ)
09:07 katsmeow-afk The requested object does not exist on this server. The link you followed is either outdated, inaccurate, or the server has been instructed not to let you have it. Nah nahh na-na-nah.
09:17 katsmeow-afk datasheet curves say the distorton of that chipis over 10% at 50v output
09:18 katsmeow-afk ah diff voltage supplies
09:19 katsmeow-afk and they compare the dc rails with a Vrms ac output
09:19 katsmeow-afk so yea,, i'd expect with 100vdc rails to see severe distortion at 70Vrms ac out
09:20 katsmeow-afk anyhoo, $8 on ebay
09:22 katsmeow-afk "no, just because they are hollow, does not mean they are hallow"
09:28 tsmeow-afk goops her
09:29 katsmeow-afk ah,, David whatshisnick, the 2nd smartest Canadian ever
09:34 katsmeow-afk David Suzuki
09:35 katsmeow-afk http://www.davidsuzuki.org/
10:01 Tom_itx zhanx, what about a bbb
10:04 Tom_itx http://beagleboard.org/BLACK
10:05 Tom_itx much better than pi
11:20 katsmeow-afk "no, i said it is a deciduous grass, not a delicious grass"
11:22 katsmeow-afk are snow geese a protected species?
11:33 katsmeow-afk "it was a SAILING warship, not a SALINE warship! jeese, you think they made warships from salt?!"
11:36 tsmeow-afk re-goos her arm before going back out
11:38 Tom_itx they tried making them from ice
11:38 tsmeow-afk
11:38 katsmeow-afk and sawdust-ice too
11:39 Tom_itx yup
11:40 katsmeow-afk the latest episode of TBBT, she asks him if he is going to be that way all night, and he said he didn't know the future,, yrs go someone asked me the same thing, and i said the same thing, and i had wondered why they changed the topic to fortune telling
11:45 katsmeow-afk there was asto the repeatedly asking the same queston over and over, and i asked why, and i was told so i would learn something from it
11:45 katsmeow-afk they asked me what i learned, i said i learned to stay away from you because you repeatedly ask these stupid questions
11:46 katsmeow-afk years later, i learned they assumed i would jump to false conclusions based on complete lack of data, the same way they had, and that they believed they had the answer, and were trying to teach me how to jump to bad conclusions
11:47 katsmeow-afk this is also under the heading of "how to piss off your mom":
11:47 katsmeow-afk the road is wet
11:47 katsmeow-afk <her> it rained last nite
11:48 katsmeow-afk it's wet only where the lawn sprinklers are
11:48 katsmeow-afk <she... throws a fit
11:48 katsmeow-afk <her> then why did you ask me?
11:48 katsmeow-afk to find out why you ran the lawn sprinklers when it rained last nite
11:49 katsmeow-afk <she... blows up
11:49 katsmeow-afk i... leave
11:50 katsmeow-afk i was always afraid to open my mouth
11:52 katsmeow-afk <her> you catch more flies with honey than with vinegar
11:52 katsmeow-afk <me> i will remember that for when i need to catch flies
11:52 katsmeow-afk <her> why would you want to catch flies???
11:52 katsmeow-afk <me> i have no idea
11:52 katsmeow-afk <her> then why are you remembering that?
11:53 katsmeow-afk <me> because you told me it, so it must be important
11:53 katsmeow-afk <her> no it isn't
11:53 katsmeow-afk <me> then why did you tell me??
11:53 tsmeow-afk s
13:42 katsmeow-afk lunch is being nuked
14:09 rue_shop3 I saw sunup yesterday...
14:09 katsmeow-afk lunch is gone!
14:09 rue_shop3 last night that is
14:10 katsmeow-afk you saw sunup last nite? cool, that's like me getting a sunburn at 10pm!
14:26 tsmeow-afk suddenly got lazy and ponders a
14:27 katsmeow-afk i been moving stuff, and right now the baby trailer is on the boat deck, so i can do an axle-ectomy on it
14:27 katsmeow-afk even if all i were doing is lengthening it from 6ft to 8.2ft, i'd still need to relocate the axle
14:29 katsmeow-afk the baby trailer isn't badly built, it's just 47 inches wide inside and 6ft long,, whe yu need to move 49 inch stuff 8.1 ft long, it's a little cramped
14:31 katsmeow-afk the way it's built, splitting it to widen it another 2 inches, and then lengthen it 2.2ft, and then relocate the axle,, faster to build a new trailer
14:31 katsmeow-afk and a new build is stronger than patching the old
20:17 katsmeow-afk met the new neighbor, he seems nice
20:18 katsmeow-afk while over there, the assholes who have been vandalising this end of the street came by, and they were notpleased to see himputting a gate up on his driveway
20:27 Tom_itx maybe he will treat you better
20:27 katsmeow-afk so far, he has
20:27 Tom_itx that's encouraging
20:28 katsmeow-afk he's my age, works as a machinist, lived 2 yrs on his own boat, makes his stuff like i do
20:28 Tom_itx that's cool
20:28 katsmeow-afk intelligent, practical
20:31 tsmeow-afk wonders what's for di
21:13 katsmeow-afk oh mybodyissore
21:25 tsmeow-afk pours some
21:29 katsmeow-afk gop goop