#garfield Logs

May 29 2015

05:51 katsmeow-afk http://www.daxtron.com/newest.html
06:39 katsmeow-afk feet, feat, fete
06:40 katsmeow-afk Fultondale ... Fool tahn da ley
06:40 katsmeow-afk envelope ... en vlapy
07:00 katsmeow-afk lathe ... lat he ... latte
08:23 katsmeow-afk SWITH MODE POWER SUPPLIES (SMPS)
08:43 katsmeow-afk so putting five irf830's in series should work as a linear current source up to 500v drop and 500ma load
08:44 katsmeow-afk even shorted to gnd at max psu voltage and max load, it's 50w per to-220 fet
08:45 katsmeow-afk obviously, one would lower the psu voltage under that condition, just to avoid having a pricey 250w heater
09:05 katsmeow-afk or, five MJ15003 will deliver an amp at 500v
09:06 katsmeow-afk 15003 are ~$1.20 on ebay from china
09:07 katsmeow-afk i have 100's of IRF830 for free
09:32 katsmeow-afk N-channel 80V and 100v, 4.4mohm and 3.3mohm , standard level MOSFET from NXP in TO-220 or I�PAK ; PSMN Series MOSFETs ; PSMN4R3-100PS , PSMN4R3-100ES , PSMN3R3-80PS , PSMN3R3-80ES
09:34 rue_house morning
09:35 katsmeow-afk meowring
09:36 katsmeow-afk it smells like a hv upgrade for the irfz44 and irf1404
09:37 katsmeow-afk starts to come on at 3.5v, is full on at 5v
09:38 katsmeow-afk i thought you might want to know
09:38 rue_house ok
09:39 rue_house I think the world forgot the difference between a pulse stretcher and a pulse detector
09:39 katsmeow-afk seems plain to me
09:43 katsmeow-afk "The little
09:43 katsmeow-afk bonding wire inside the HV FET/IGBT *will easily* have enough inductance to
09:43 katsmeow-afk overvolt the gate and kill the switch
09:43 katsmeow-afk "
09:44 rue_house oooh
09:44 rue_house right, a fet as a variable capacitor
09:45 rue_house you can use the fet to boost voltage by playing with the distance of the plates
09:45 rue_house go from lightly off to really off
09:46 rue_house charge the plates with high seperation, decrease seperation, have higher voltage
09:50 katsmeow-afk i don't tink you can multiply voltage by changing plate separation
18:45 katsmeow-afk i think i need another bridge crane
18:46 katsmeow-afk it would make moving boat parts safer, and i could move one to the boat itself as soon as i need it there
18:47 katsmeow-afk grrr,, that will set me back anotehr month's worth of money
18:47 katsmeow-afk not quite that bad
18:48 katsmeow-afk $80 for the bridge, i can use a winch i already have, i can use scraps of steel i already have
18:48 katsmeow-afk battery i already have
18:48 katsmeow-afk $80 and some time,, grrr
18:49 katsmeow-afk trip to store, bbl
20:32 katsmeow-afk .
20:33 katsmeow-afk the boat is 16ft wide, the rails here are 14ft apart
20:50 rue_house its a physics thing, as the distance between the plates varries, the voltage changes
20:50 rue_house you didn't know thatone?
20:51 rue_house thats how a scanning microscope works
20:53 katsmeow-afk fora given current off the tip, yeas
20:54 katsmeow-afk as you pull the tip away, the air resistance goes up, the voltage drop is less, so the tip voltage goes up
20:54 katsmeow-afk got nothing to do with capacitance unless you made an ac SEM
20:54 rue_house er, what, is scanning evacuated?
20:56 rue_house do you have "modern university physics" circa '64?
20:56 katsmeow-afk no, prolly might find it, or somethinglike it
20:57 rue_house I made an orange board with black stripes for the robots to sit on at the fair
20:57 katsmeow-afk A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons.
20:57 rue_house or a black board with ornage stripes...
20:57 rue_house anyhow, it hurts my eyes
20:57 katsmeow-afk https://en.wikipedia.org/wiki/Scanning_electron_microscope
20:57 rue_house whats the one that uses a flying needle?
20:58 katsmeow-afk yeas
20:58 katsmeow-afk it was Manfred von Ardenne who in 1937 invented[4] a true microscope with high magnification by scanning a very small raster with a demagnified and finely focused electron beam.
20:59 rue_house which one uses a needle
21:00 katsmeow-afk it's basically the same way you can read some oscope crt's instantly after they are written with a signal trace: the glowing portion of the crt face has a higher resistance than the unglowing portions, if you raster scan with a low current current-source, you can pick off voltage differences from the electron gun as it crosses lit portions of the crt face
21:01 katsmeow-afk someone posted a webpage of a diy sem witha needle
21:01 katsmeow-afk i forget whowherewhen
21:02 katsmeow-afk the modern beam, instead of apoint source needle, is like a crt electron gun
21:04 katsmeow-afk many results : https://duckduckgo.com/?q=diy+scanning+electron+microscope
21:06 rue_house arg, I nap now