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Thread: Transistor recommendation

  1. #1
    Junior Member
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    Aug 2017

    Transistor recommendation

    There has been three people inside the chum [teepee]--my husband Ivan and i also,
    as well as the old man Vasily. Out of the blue someone gave our chum a difficult jolt. I
    was startled, cried out, and automobile up Ivan, therefore we started to climb out
    in the sleeping bag. Again someone gave our chum a difficult jolt, therefore we
    fell down. Old man Vasily fell on top people, as if someone had tossed him in mid-air.
    There's noise throughout, someone was how to choose a sleeping bag
    making noise and banging round the ellyun [the reindeer hide covering of
    the chum]. Out of the blue it increased to get very light, an exciting sun was shining here
    plus a strong wind was blowing. Then someone fired a mighty shot, as if
    ice was exploding the way does throughout the cold several weeks round the Katanga,
    plus a dancing Uchir [tornado] immediately swooped lower and grabbed the ellyun,
    started to twist it and spin it then transported it well somewhere. There
    was nothing left nevertheless the dyukcha [frame in the chum]. I used to be scared out
    of my wits and started to go to bucho [lose awareness] I saw the Uchir
    dancing. I cried out and immediately came back to existence. The Uchir dumped
    the entire dyukcha on me and banged up my leg using one of the rods. I
    crawled from beneath the rods and started to be sad: stomach while using
    dishware happen to be thrown in the tent plus it was lounging a lengthy way away,
    opened up up and with a lot of the cups broken. I used to be searching at our forest and
    I possibly could not notice. Many tree trunks were standing branchless, leafless.
    Many, many trunks were lounging on the ground. Dry tree trunks, branches,
    and reindeer moss were burning on the ground. I looked and saw
    some form of clothing burning I walked up and saw it was subsequently our
    rabbit-fur blanket as well as the fur sleeping bag that Ivan and i also rested in.
    An exciting summer time time night dawned as well as the fire began to die. As opposed to
    heat we started to own cold. We made a decision to move toward the Katanga. All
    around were wonders, horrible wonders. It was not our forest. I'd never
    seen this kind of forest. It absolutely was some form of alien forest--we'd a thick
    forest, a vintage forest. Now in several places there had not been forest at
    all. Round the hills, all the tree trunks were lounging lower, plus it was
    light, and you may see everything off inside the distance. However, you
    couldn't walk-with the swamps within the ft in the hills: some tree
    trunks were standing some were lounging, some were leaning, some had fallen on one another.
    Many tree trunks were burned, as well as the dried sticks and moss continued to be as burning and smoking.

    SUCH WERE THE Remembrances from the Evenk lady named Akulina in regards to the occasions of the summer time 30, 1908 inside the Siberian taiga. Today, a hundred years later, all the eyewitnesses have handed lower, yet, due to the dedicated work of scholars, we have their first-person accounts--and a lot of people saw and/or heard the strange explosion that resounded coming inside the Podkamennaya Tunguska River (the headwaters which Akulina describes since the Katanga), an area very distant in the community.

    If you are capable of going past the tales which report that the Tunguska increased to get filled with doppelgangers--clones separated by a few kilometers, or even the Evenk god Ogda travelled within the sky, there's great similarity inside the many accounts. Clearly there's a substantial rumble many individuals thought that an earthquake had begun in many places, houses much sturdier than Akulina and her husband's chum were shaken and jolted an exciting fire exhibited coming--some described it created as being a sphere, others, as being a barrel but nonetheless others as being a huge, fiery broom.
    November the Tunguska meteorite--when the was, really, a meteorite--remains most likely probably the most alluring mysteries in the last century, as well as the ranks of people attempting to solve it are growing rather of shrinking. You'll find numerous explanations that happened--some harebrained, some getting a means of calculating science inside it. Possibly an enormous meteorite smashed to the earth in 1908, or even it absolutely was an asteroid or possibly a comet. Possibly a substantial gas bubble steered obvious of from local swamps, or even it had been the crash from the spaceship from Mars ... As well as the notion that the hearth god Ogda may have been chastening people for defiance has furthermore not disproved.

    While each one of these versions may have their merits, each one has somewhat problem. Nobody has yet formulated a concept that explains all the evidence which has been discovered inside the taiga. Unanswered questions always seem to stay almost always there is a lingering "but ..." Possibly because of this there is no finish to the quantity of people associated with trying to finally eliminate every one of these "buts." Enthusiasts from Krasnoyarsk, physicists from Italia as well as the united states . States, authors of fantasy literature, geologists, and astronomers still grapple using this puzzle.
    An individuals story behind the Tunguska enigma is not less how to choose the right sleeping bag amazing when compared with enigma itself. Why, after careers just like a forest ranger, surveyor, revolutionary, and soldier, did Leonid Kulik out of the blue decide to devote themselves to review regarding meteorites and organize several expeditions for the taiga between 1927 and 1939, expeditions that collected extensive evidence in regards to the occasions of 1908? What motivated him? Possibly he believed that the " " New World " " that was emerging following a revolution required to open uncharted expanses for understanding and science? Or even inside the 1930s the taiga was only the best place to pay for--in the bloody Terror and human wickedness? What did the folks of Kulik's expedition discuss across the fire in 1937--along with what were they afraid to discuss? The thing that was foremost by themselves minds--obtaining a meteorite or news in your own home, where their loved ones might disappear without any trace? Or was Kulik simply spellbound with the regal and mysterious arena of the taiga? Furthermore to his scientific articles, he described his analysis in verse (box, right).
    Did Leonid Kulik think about this crater while he lay dying in the German prisoner of war camp in 1942? Among the horrors of war, how distant the enigmatic tranquility in the taiga must have made an appearance.

    And why, inside the 1930s, was the youthful engineer and inventor Alexander Kazantsev out of the blue gripped while using urge to produce his first novel, Flaming Island? Within it, a horrifying environmental disaster that threatens everyone is actually proportional with a cosmic accident involving, in Kazantsev's vision, the wreck from the Martian spaceship inside the taiga in 1908.
    Kazantsev's book had all the correct ideological trappings, with villainous American capitalists and Japanese spies pitted against Soviet scientists and soldiers. He was consistent with the party line for the finish of his extended existence, as well as the novels he printed inside the 1970s were unbearably dull. But Flaming Island ([TEXT NOT REPRODUCIBLE IN ASCII], which does not seem to possess been changed into British) features a certain fascination--however diluted--mainly due to the Tunguska mystery also to the novel's periodic flashes of inspiration, like the delivering of space ships to Mars or the threat of planetary suffocation because of burning atmosphere.

    A completely new spike in fascination with the Tunguska meteorite mystery incorporated its fiftieth anniversary in 1958. This can be understandable. The Soviet system had softened just a little--inadequate allowing political freedom, yet it absolutely was simple to accept in addition to romanticize "unusual behavior," avoid workaday existence and city air, and, consequently, from official structures and ideologized behavior. This can be a good reason that most likely probably the most romanticized professions in those days was geology, an activity that is not, it may look like, an easy one. The appearance in the geologist wasn't someone elbow-deep in dirt who avoid seeing home for many days at any time, but somebody who dons a sweater plus a extended beard, and spends time on expeditions, where he plays his guitar and sings around evening campfires. The term "expedition"--whether geological, archeological, or paleontological--was captivating. An expedition meant freedom an expedition meant a distinctive, outstanding existence. Plus an expedition attempting to solve one of the great mysteries within our occasions was doubly alluring.

    It's really no coincidence that 1959 was the season the Integrated Amateur Expedition happened, an effort whose participants to this day are striving to solve the mysteries all over the occasions of 1908. The KSE (becasue it is acronym reads in Russian) includes a mixture of serious scholars and romantic dreamers, along with, clearly, oddballs and ordinary those who simply enjoy backpacking using the taiga. You'll be able to laugh their way or shrug shoulders, or admire their persistence and persistence types of sleeping bags for camping. But in the event you start to see the enthusiasm they describe how they lug their backpacks along "Kulik's Trail," as the direction to the web site in the disaster has been known, you'd understand the possible lack of true mystery in lots of within our lives.
    Maybe it genuinely was Ogda flying inside the taiga within the finish?
    The center of the end result I walked throughout!
    As being a fiery spray of incandescent gasses
    And cold physiques
    The meteorite smashed in to a hollow
    Having its hillsides, its tundra, its swamp
    And, as being a spray water,
    After punching the fine surface,
    It sent an infant shower
    To all or any four corners,
    Much like the spray
    Of incandescent gasses getting a cluster of physiques
    Permeated our world
    Which is immediate effect,
    Additionally to
    Its explosive reverberation produced
    This complete picture of destruction.
    Last edited by firosiro; 09-18-2017 at 09:13 AM.

  2. #2
    Senior Member
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    Dec 2016
    Montreal, Canada
    i would use logic level mosfets, but thats just me

  3. #3
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Unless you do something to intentionally slow it down (like a fancy opamp circuit), pretty much any transistor will switch on/off much faster than 1 millisecond.

    Many very smart & experienced people read this forum. But when you ask a narrowly focused context-free technical question, there's no possibly for anyone to understand what you're really trying to accomplish. Perhaps there's some hidden gotchas with the type of thing you're driving? (like inductive or back-EMF voltage spikes....) Maybe someone knows about certain parts or techniques that could help you accomplish your goals more efficiently, perhaps specialized parts or maybe even optimized ways to do something that doesn't need as many parts? But without context, without understanding of what you're really trying to do, without even any idea of what these transistors are meant to actually turn on/off, nobody can use any of that experience to help you.

  4. #4
    Junior Member
    Join Date
    Jul 2017
    Austin, TX
    How much current?
    How much Voltage?
    What is the nature of the device you are trying to control?

  5. #5
    Senior Member
    Join Date
    Dec 2014
    Yeah, you really want to use an n-channel MOSFET, not a NPN.
    For a hundred milliamps or so, the BS-170 is my go-to. It switches fast, tolerates up to 60V, is well driven by 3.3V I/O pins, and has an internal resistance of about 5 Ohms.
    For anything bigger, I just plug my required parameters into Digi-Key parametric search and see what they come up with.
    N-channel MOSFETs work great as low-end switches, i e, the source hooks to shared ground between load/MCU, the gate hooks to the MCU pin controlling it, and the drain hooks to whatever load you have (which then in turn hooks to your power supply positive.)
    Your load power supply can be much higher than the 3/5V of the Teensy in this configuration, as long as it's less than the rated Vds for the transistor you're using. (60V for BS-170.)
    As you may know, MOSFETs just consume a little bit of current while charging/discharging the gate, and otherwise do not consume any current in stable state (on or off.) They also have, usually, low internal reistance, and thus can run quite high loads without additional heat sinking (depending on which particular device.)

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