Connect with us

Beginner coilgun questions

Discussion in 'Electronic Basics' started by Ross A. Finlayson, Feb 22, 2004.

Scroll to continue with content
  1. I try to build a coilgun.

    The coil is better at the beginning of the winding than towards the
    end, there are five or six gaps of a millimeter or so in the latter
    half of the coil. I started by drilling a hole through the 1/2" inner
    diameter PVC pipe and threading an end of the wire through it, then
    wrapping the wire as tightly as feasible by hand around the pipe, with
    the threaded end acting as a backstop. I wound twenty or thirty
    coils, then drilled another hole at six inches from the first and kept
    winding until that was reached, then the wire was snipped from the
    spool giving a foot or so extra and that end threaded through the
    second hole. The first hole didn't have enough coming through to work
    with so I pulled it out and unwound a coil and rethreaded it.

    The coil is almost decent, the average diameter is pretty good as it
    is wound tightly around the pipe, but there are five or six gaps of
    about a millimeter. I try to even those out. I have access to lots
    of 10 gauge round and square magnet wire.

    So now I plan to tape the coil to help hold it in place, then pull the
    end out of the PVC to be the leads. It might be better to use an
    epoxy to hold the coil down, but I plan to just leave it on there a
    couple days and handle it and figure it will come to rest in its
    coiled form. I put tape around the coil, and pull the backstops, it
    spreads a little.

    The wire is some surplus wire, it looks like copper wire and is soft
    enough to turn by hand, but some of the insulation has come off and it
    looks like aluminum. The spool says 11 gauge wire, the wire is about
    3/32" in diameter. It has about 62 1/4 turns that will be usable, one
    winding, in a 5/8" inner diameter coil that is about 6" in length.

    I got from Radio Shack, the local 'lectronic parts retail outlet, a
    bag of assorted resistors and one of electrolytic capacitors, and some
    LEDs and a battery case to hold four 1.58V AA batteries, and some
    circuit board, I wanted to get but didn't see one of those 9V battery
    posts. I look through the capacitors from the three dollar capacitor
    assortment and the biggest ones are only 47 microfarads at 200 Volts.
    I can wire three of them in parallel for basically a capacitor of 141
    uF at 200V. That is not a large enough capacitor.

    I search the Internet for car audio capacitors, they have ones with
    extra digital baggage that are some 2.5 farads, 24V, for a hundred
    dollars or so. To charge something like that I would instead of
    alkaline batteries be looking towards 6V motorcycle batteries, or a
    12/13.8 volt automotive battery, or a transformer fed with wall
    current. I read that adding EDTA powder dissolved in distilled water
    helps with desulfonation of liquid electrolye lead acid batteries.

    So I guess I should tape this coil and wire its ends into modular
    leads of some form, then I will be running various wires into the
    leads. I think I should start with low power and just try to get an
    idea using a couple cheap multimeters what happens to the coil with
    various inputs, and if it is of enough power to draw these wood screws
    in a dowel into the coil, then I can run the dowel through by hand and
    help determine if I can use some effects of the variable solenoid to
    automate the switching.

    I look for a model to Barry's Mark II coilgun. I only have puny 47
    microfarad capacitors here, where his design is using a 28000
    microfarad capacitor. I take the piece of circuit board and lay out
    the wires and components, three of those capacitors in parallel, an
    10000 Ohm bleed resistor, and the line with the coil and the SCR, for
    each from positive to negative. I don't have a diode protecting the
    capacitors. I solder the wires and components, and connect the wires
    to the power supply (four ganged AA batteries) and the coil. I test
    all the connections as possible. I put on safety goggles, because I
    am afraid of the capacitors, and put the batteries in and then apply
    the gate charge to the SCR with the 9V battery. The screw sits
    obstinately in the coil.

    I conclude perhaps the coil is bad, I fried some element, the power
    supply or capacitance is too weak, I assembled it incorrectly, or the
    power supply is too weak.

    I connect the battery pack to the coil. The coil does not exhibit
    enough magnetic activity to pick up little bits of wire, it's an air
    cored coil. The battery pack grows warm quickly. I remove a battery
    to break the circuit and reassemble the other circuit. I put the
    ammeter in line between the coil and SCR. When I connect the gate
    line to the SCR some amperage goes through the coil, otherwise none.
    This leads me to believe the circuit is correct, but there is not
    enough power going into the coil. I reiterate dissasembling the
    circuit and reassembling it and repeating the SCR experiment. There
    is again not amperage into the coil until I apply the 9V, dropped over
    a 330 Ohm resistor, to the gate of the SCR which says "trigger
    current: 25 mA Typ." When I remove the trigger current stops flowing
    and the ammeter drops again to zero. There doesn't seem to be a pulse
    from the capacitors, maybe they are incorrectly installed or bad.

    + -----------------
    | | |
    R1 | coil
    | /|\ |
    | C1C2C3 SCR -- R2 -
    | \|/ | |
    | | | +
    | | | -
    | | | |
    - ---------------------------

    R1: ~11000 Ohm bleed resistor
    C1, C2, C3: 47 uF 200V electrolytic capacitors
    SCR: 1A, 200V SCR
    R2: 330 Ohm resistor

    I've put about thirty or forty hours into reading and studying,
    shopping for parts took a couple hours and assembly and testing a
    couple hours, or four or five hours. I can see the benefit of one of
    those solder vacuums. I fried an LED in connecting it to a 9V
    battery, aw, my first ruined part.

    I guess next thing to do is to get or build a transformer for working
    with wall current, with the "full-wave bridge rectifier", and see if
    that would be enough power to energize the coil, and track down some
    higher rated capacitors. What's the most "bang for buck" in

    Here's my main question: assuming I get enough power into the coil
    that it draws something into the coil, how can I determine
    electronically from the dynamic electromagnetic characteristics of the
    coil when the item has been drawn into the coil with the most force,
    to then deenergize the coil so the projectile gets maximum impetus
    from the coil? In a related question, how could I sense from a coil
    that is magnetized at low power when something enters its magnetic
    field strongly, the idea here being having feedback timing instead of
    programmed or photosensor timing?

    Please describe the design of a coilgun to launch 10000 kilograms into

    I search sci.electronics for coilguns. I read some interesting
    comment on "Does anyone see anything inherently wrong with this
    design?", taking note of "Wheeler's equation" and induced-current
    effects from motion. Here's a design schmematic from Russia:

    That design is using 47 uF capacitors, but 400V, and 150uF caps at
    400V. Oh, I guess if the capacitor is wired in series it sums the
    voltage, where I have wired them in parallel to sum the capacitance.
    I read something that said wiring the capacitors in series is 1/C1 +
    1/C2 +....

    I look to . It
    says 11 gauge wire should use around 2500V. :(

    Can a small battery charge a large capacitor? What's the cheapest way
    that I could put together a coilgun that I could carry around that
    shoots projectiles faster than my bow at 325 fps? How would square
    wire be different? Is it the skin effect? Capacitors used to be huge
    and full of liquid.

    Basically I want to drive the 62 turns of 11 gauge wire, my first
    coil, 2.2 millimeter diameter wire, 15.8 millimeter internal diameter
    coil, around 11.8 millimeter plastic pipe, to launch a 7.05 gram nail
    among ~12 grams of wood at 100 m/s. Please advise. I'm off to read
    the rabid teenagers' high voltage coilgun progress. Thank you for
    your advice.

    Ross Finlayson
  2. I need bigger capacitors.

    The idea is to construct the plates with maximum surface area, at
    minimum distances separated by dielectric materials of known

    Using some form of crystalline structure, the idea is to use a
    substrate, for example silicon, that is not flat but instead
    "fractal", similar to the etching concept in increasing capacitor
    surface area in aluminum oxide capacitors.

    Maybe the silicon could be etched by a laser, it wouldn't have to be
    precise, for example in an analogy to piston surfacers, the bottle
    brush instead of the three-stone blades.

    Then also there are many small holes left in the substrate through the
    substrate. Then, conductive material is laid over the substrate, on
    both sides, filling the holes to conduct from the smooth side to the
    righ side, and matching the pattern etched onto the rough side.

    Then two round plates are formed with an insulated ring seal around a
    solid filling of dielectric.

    The surface area of the plate could be increased in this way. The
    plates are matched in the etching so they are more or less mirror
    images of each other to maintain as much as possible an equal minimum
    distance between the two plates, to be able to have more fixed
    electrical characteristics.

    It is similar to current techniques, except the idea is to have a more
    precise surface area calculation than etching the capacitor plates
    chemically, although that works out on the macroscale to be quite
    precise and is an effective state-of-the-art method.

    The costs would be higher because etching the substrate via laser or
    mechanically is a more capital intensive process than chemically
    etching the plate. Physical plate etching could be a lot more crude
    than the substrate etching in paths to form microchips.

    I'm trying to think of how a flat plate could have its surface area
    increased the most. It reminds me of the infinite coastline. Anyways
    in a crystal structure of silicon, tetragonal, (?), the idea would be
    to carve grooves to leave lands, and the increased surface area would
    be twice the length by the depth of the groove, per parallel groove,
    in assuming some theoretical constant depth grooves with flat walls.

    In matching to the opposite plate, it might be more computationally
    tractable as a thought experiment in having a "corrugated" or wave
    pattern, for example to increase the surface area by the square root
    of three or the ratio of the sine curve length to the flat line, in
    maintaining a fixed maximum distance between the two plates.

    It could be that the distance is so huge compared to the lands and
    grooves that it is instead a question of maximizing surface area in
    contact with the dielectric without considering the plate distance,
    with deep intercrossing grooves, deeper than the width of the grooves,
    so it looks like a dull frog, one of those hedgehogs from flower

    Perhaps a chemical process is the way to go about this, with marking
    the plate with miniature regular or fractal resist patterns before
    etching. The plate could be layers of conductive films, one resistant
    to the etchant, the top layer is not, and then a resist "ink" could be
    patterned on the top layer, in assuming it is easier to form large
    amounts of layered conductor than drop beads of conductor in "fractal"

    Another thing I'm trying to figure out is how to use only part of the
    capacitance. Here I again expose my electrical/electronic ignorance.
    Say the capacitor is charged, and then I want to switch to another
    circuit, here I'm still trying to figure out how to charge a 200 or
    440V capacitor with a 1.58V battery. Anyways then I want to be able
    to dial how much power is to go into a circuit, then have the
    capacitor discharge into that and a different kind of capacitor that
    leaks current back into the battery. (Waves arms in air and screeches
    like monkey.)

    I'm looking at these ultracapacitors, they have some 10 Farads but
    only 2.5 volts. It would take a thousand of them to get 2500 volts,
    they are only rated for 2.5 amps. If a thousand capacitors could each
    handle 2.5 amps then that would mean the 1000 capacitors in series to
    increase the voltage could still only handle 2.5 Amps. On the other
    hand, if I find a thousand 2500V capacitors and wire them in parallel,
    and each could only handle 1 mA, then together they could handle an

    There are these microwave oven capacitors, they are at 2500V, then
    some of these motor capacitors are at 440V, but each are less than 1F.
    I read now described a 15000mF 600V phase correction capacitor. Ah
    dang, it was 15000 microfarads, not millifarads: 15 mF.

    I'm ignorant, I think a Farad can put an Ampere through a circuit with
    no resistance. Hmm.... I guess the capacitor with a higher
    capacitance/voltage ratio will discharge faster. That has to do with
    the timing of the capacitor charges, another large emptiness in my

    Q = V C

    The charge in Coulombs in the capacitor is the voltage in Volts times
    the capacitance in Farads, where a Coulomb is "a great many multiples
    of the charge of an electron per second."

    So I guess I'm looking for high power high voltage small time constant
    small form factor capacitors, and a high power low voltage capacitor
    with a large time constant to recharge batteries.

    So now I'm trying to figure out how to light an LED when a capacitor
    is fully charged. That, and those capacitors.

    Electronics is an interesting hobby. For some, it's a profession.
    Personally, it's confusion.

    Ross F.
  3. You are going to a lot of trouble to invent nothing new. Talk to
    FEerguy about this; he will rant and wax eloquent.
    The idea will not work because the more you carve up the surface to
    increase the area, the more susceptible to insulation breakdown the
    dielectric becomes. And the more deeply curved and convoluted a surface,
    the more readily it emits charges at those points.


    Chip Shults
  4. I wonder about this then: using multiple types of dielectrics. One
    type with given qualities fills all the nooks and crannies, forming
    basically a flat surface with the grid of the conductor on the flat
    surface, another dielectric with lower "breakdown voltage" forms a
    fixed distance between that grid and the other. The conductor still
    has large surface area exposed to dielectric, but the current path
    woud be through fixed distances between the grid points.

    Another concept is using the method where the aluminum is deposed on
    the silicon substrate that is drilled "checkerboard", with leaving the
    posts of smaller dimensions to deposit the thin film of aluminum
    covering those posts, then converting a layer to aluminum oxide, then
    depositing more aluminum to create the mirror image of the posts, yet
    slightly less to make up for the silicon in the cathode's, then saying
    that that has a higher surface area yet the minimum distance between
    anode and cathode is near constant. This is where I think that the
    breakdown and current flow is through the least amount of dielectric
    (insulator) where the aluminum is assumed to be a perfect conductor,
    and the thinnest bridge of insulator the path of least resistance.

    Another concept is to have many thousand of microminiaturized
    capacitors in parallel. They could have high voltage individually and
    high capacitance together. My visualization of that is two flat
    plates connected by millions of conducting threads through an
    insulator, and then a laser excitation process converts a section of
    each thread to dielectric, thus that each thread becomes a high
    voltage capacitor. (<- Probably nonsense.)

    Maybe instead of a capacitor I could use another pulse discharge
    source, for example the Marx Generator. I just heard of that but it
    seems that it would still require the capacitors, they are just
    charged in parallel and activated in series, with still requiring high
    power high voltage capacitors, but with the ability to charge them
    from a lower voltage source.

    I don't understand what "ground" is. I understand that a metal rod
    sunk into damp earth is a "ground". If you put two electrodes in wet
    ground the worms crawl to the surface, providing bait.

    High voltage (~2500V) high capacitance (>100mF) high current (>10A)
    small time constant (<1) small form factor (<soda or soup can)
    capacitors: I think I need some of those to energize an 11 gauge
    motor wire coil with 60+ turns on one winding to activate the Lenz
    potential (?) to launch the test projectiles at >100m/s. Then again
    it might only require a bunch of 400V 10mF capacitors.

    That might be fun but consumer electronics run on a quite different
    beast: low voltage, vast vistas. Also some of them use alternating
    current (AC) instead of direct current (DC), another deep trench of
    personal ignorance.

    Please describe a design of a coilgun that can launch 10000 kg to

    I need to have a better understanding of DC-DC conversion for charging
    the capacitors to their rated voltage. I think I should use a 12V
    power supply, or perhaps 6V, and then I want to have 250V from that.

    I can get hundreds of volts from the AC power line, the transformer
    steps up the AC voltage that is then rectified. Yet, I prefer to do
    only very simple and uncomplicated repair or work on wires that I plug
    into the wall.

    I have heard talk of "flyback topology" and whatnot and am uneducated.

    I think that I want to charge the capacitors, and then break the
    charging circuit, and then connect the launching circuit. Then there
    is to be a separate switch to connect the capacitors to the bleed
    resistor, to safely discharge the capacitor(s)/capacitor bank.

    I am concerned about wiring the capacitors in series, "summing" their
    voltage, in applying that voltage to charge them it is beyond their
    rated voltage, and with more than two in series beyond twice the rated
    voltage. Some capacitor notes explain that the capacitor can handle
    twice the rated voltage for a short time.

    Here when I say capacitor I generally am referring to the polarized
    capacitor, electrolytic in construction. I need to prevent much
    backwards voltage when the field collapses, using the diodes to charge
    another capacitor in reverse to the launch capacitor that is to
    trickle current back into the battery.

    The diodes should have some capabilities to switch multiple paths
    nearly instantly. The power goes in and out, but some of the
    components are one-way, in this simple direct current consideration.

    The thing needs to have a variety of indicators to show the metered
    voltage in the capacitor bank and the current going into the
    capacitors and stuff. I searched for the cheapest voltmeters I could
    find, I guess it would be least expensive to get some LCDs and wire
    them with an IC linked to one of those voltage-varied 'sistors, but
    that is getting more complicated than where I still am having
    difficulty understanding how and why transistors are used to effect
    current bias. Anyways it is good to have a meter or even some kind of
    meter bus, transferring meter data from multiple points to a central
    display or serial/parallel connector, yet that again often involves
    the use of low voltages and perhaps an external/isolated circuit.

    Also the whole thing is supposed to be able to handle several amps.
    That involves heavy wire between the capacitor bank and coil.

    Back to the DC-DC converter, stepping up from 6V/12V to 250V, for
    charging from a car battery or hand crank to 250V, I don't want to
    convert to AC then multiply the voltage and convert back. Maybe a
    flash tube is in order. Maybe a flash tube is on order.

    I guess I really need a variable DC lab bench power supply. The idea
    with one of those is to use the AC power from the wall and step up the
    AC voltage to higher than the maximum DC output of the power supply,
    then rectify that to DC, in using one AC transformer instead of
    switching among a multitude. Then, regulate and divide the output

    In reading about the DC/DC converter, the
    oscillator/transformer/rectifier, I am looking here at some designs
    that don't use ICs, integrated circuits of diodes, resistors, and
    capacitors, but rather an oscillating transistor. I could acquire a
    115V->12V transformer and reverse its operation, but I want 6V->250+V.
    I guess I could find a 250V->6V transformer and reverse its
    operation, for a 6V->250V inverter. Building one would probably be
    less efficient than procuring one. Yet, in building one, I could do
    without much besides plain square wave output rectified, a
    plain-ol-plain-ol DC-DC converter. Yet, I want one without oscillator
    and coils. Let's see, if I wind a coil that is 12cm in length around
    one of 250cm in length, I don't understand. The coil design for the
    coilgun stepup transformer for DC/DC conversion is probably of the
    "soft-iron" core, with the idea to match the coils for maximum flux
    match for efficiency. Also there is the primary coil and the feedback
    coil for the two stages of the DC current to make the square wave AC
    to induce the AC current in the secondary. So I would have a primary
    and feedback coil each of, say, 6 turns and the secondary of 250
    turns. By this time I am thinking about various taps of the coils,
    with the contacts among the coils, for example for 12x2 -> 250. Then,
    the leads to the secodary have modular connectors to be replaced with
    the rectified wall current or variable DC power source.

    I'm concerned about the capacitors. If I wire them in series and
    charge them to twice the rated voltage (250V x 2 = 500V), or, say,
    thrice or four times, will that damage a capacitor?

    Thank you for your advice,

    Ross F.
  5. Hi, Ross.
    Multiple layers of different dielectrics can overcome some problems,
    like improving insulation breakdown, but a checkerboard pattern would be a
    bad idea- think of the corners. Any time you have sharp angles inside a
    capacitor, you have automatically limited its voltage rating.
    If you exceed a capacitor's rated voltage, you will likely damage it.
    You will certainly shorten its life. If you discharge a capacitor rapidly
    and it does not have a low ESR, then you will induce heating. You can't for
    instance use a standard electrolytic as a photoflash capacitor. It will
    heat rapidly and explode.
    There are some caveats about capacitors, and it might do you some good
    to take the time and get a good book from the library. These are not
    necessarily obvious things, but things that many people learn over a period
    of time while learning electronics. So don't feel discouraged.


    Chip Shults
  6. Haiti was the second democracy in this hemisphere after revolting from
    France in the 18th or 19th century.

    I try some more studying. I'm not completely ignorant about
    electronics an d electricity and magnetism, just mostly, yet I can't
    claim my ignorance in defense of of my incompetence because like many
    people who want to write their own operating systems and executives
    someday I have browsed the Intel Pentium microprocessor manuals, ARM,
    Alpha, SPARC, and have a couple PC hardware books, video card book,
    PCI manuals, boot specifications, IDE and SCSI, browsing Linux source
    code for PCs and PDAs, about any of which I am quite ignorant.
    Software and even relatively sophisticated software interfaces I can
    handle, hardware (electronics) is more caveman poke wire with

    I was talking to the Radio Shack guy about the transformers. There
    are Radio Shack parts, they sell step-down 120VAC/12VAC transformer
    coils prepackaged with the armature that compresses the flux and
    reduces electromagnetic interference, rated to some four amps, or so,
    although I'm still trying to get a grasp on what is the transformer
    rating "VA" for volt amps. So anyways I described my idea that I
    would reverse its operation with a square wave input from 12VDC
    oscillated to 12VAC to the secondary as the primary thus that what had
    been designed as the primary had an output of 120VAC, rectifying that
    to get 120VDC. He was telling me that the output would not be so good
    because the mutual inductance would suffer for the square wave input.
    Anyways then I asked about other DC-DC converters and he described a
    transistorized system that I would like to learn more about generally.

    Searching for transformers yields very many of them, for example many
    or most of the cords that plug things into the wall have one as part
    of their power supply. It seems like a 2.5V/115V transformer rated at
    10A coud be used with 6V input to get 115*6/2.5 V output, yet the
    input might need to be not a square wave but crudely a sine wave.

    The library had an electronics book, I have read their books about
    wiring code compliant house systems with electricity, they require
    outlets all over the place. It's pretty good, it complements the
    "electronics one-seven" from the 70's with a nice introduction to
    vacuum tubes, "Teach Yourself Electronics" or something, from Tab
    books, the publishers of some nice laser project books. From Radio
    Shack I have a stack of those Forrest Mims pamphlets and "Building
    Power Supplies." I like to browse the Artech House catalog. The book
    is pretty good, it has helped me organize some thoughts.

    Much information readily available over the Internet is often really
    excellent. There are just hundreds of thousands of high quality
    amateur, hobbyist, and strictly professional tutorials, manuals,
    how-to guides, et c. Two excellent sites:

    Another great source of information on the internet is those damn
    voluble ham radio enthusiasts. They are happy to describe their
    projects in detail. I read this one book about building your own
    satellite downlinks, that was pretty cool, basically the
    premanufactured part to buy is the transducer.

    The specification sheets of the components themselves are often very
    educational about what reasons people would select the component. For
    example, here where we have been talking about capacitors, I have no
    idea what the E.S.R., ESR, of the capacitors I have are and have
    forgotten what its acronym expands to: Equivalent Series Resistance.
    I think the photo-flash capacitors have qualitatively lower ESR, and
    I'm trying to understand what the voltage, capacitance, ESR, and "time
    constant" of the capacitors have to do with their discharge.

    Another thing I'm trying to consider are such things as inrush
    voltage, inrush surge voltage and current. Basically I want to send
    an electrical field into the coil: the electrical field movement
    creates a magnetic field, and then remove the current, magnetic field
    movement creates the back EMF electrical field, but why does the
    magnetic field move when the current is removed? Is it because the
    conductor is not magnetized because its little sections or elements?,
    atomic moments? are not fixed by the flux? Yet, if you wind a core
    with a coil, and charge the coil, and hit the core with a hammer, it
    might become magnetized, shaking the "crystalline" metallic structure.

    That's an interesting description of some forms of magnetism.

    I want to address the theoretical capacitor for a moment, the
    "checkerboard", you noted that the conductor should not have sharp
    edges. I think this has to do with the "skin effect", where the
    current flow in a conducting wire is concentrated on the surface of
    the wire, not the center. Anyways instead of square posts, perhaps
    the posts could be circular, cylindrical, yet sometime it's easier to
    draw a straight line that a good circle on little dang microscopic

    About overcharging the capacitors, I actually don't want them to
    malfunction destructively or otherwise. I figure what I will do is
    take a couple as spares and testing units and charge them in series as
    a pair to then twice their individual rated voltage, or one at a time,
    preferably in a well-ventilated area wearing safety equipment and with
    a stable power supply, and observe them. To physically measure the
    capacitance figures to determine the extent of permanent electrolytic
    failure might then require a capacitor meter device of some form.

    I came across some references to superconductors, there are advances
    and they are being considered in many applications. Yet, that is
    quite beyond my renaissance caveman capabilities to pour the sintered
    molds to form brittle superconducting coils that are then highly
    thermally insulated except for one little bit that is exposed to a
    refridgerant line, with Peltier or Seebeck junctions on the connectors
    to the wiring.

    So anyways I'm trying to understand the suitabilty of inexpensive
    premanufactured transformer coils in stepping up 6V or 12V of direct
    current to about 250VDC. Also I'm hoping that you can tell me about
    the transistorized DC/DC upconverter, the guy was telling me I would
    probably be using 10 watt wire wrapped resistors for that.

    Please explain some general concepts and methods of voltage conversion
    and heuristics of what current flows through a circuit.

    Also, about the capacitors, thank you for that information, I guess
    the component sheets have detailed manufacuring specification, and
    then there is some variability.

    I guess that's one reason software, digital logic, is in a way more
    conducive to conceptual tractability, the bit is on or off. I guess
    in quantum computing the bit is on and off and that is N-d instead of
    the circuit, network, or graph, graph theory. In analog circuitry
    it's even worse, the graph is one big continuum. Luckily... never
    mind, maybe later.

    I wonder if in the future that to make pretty much any logic circuit
    will be a matter of playing a hologram to burn the circuit into little
    translucent cubes.

    I can get some more capacitors, what I need to do is get a power
    supply figured out, then I think I'll be trying to figure out how to
    get some good results with the coils. Then, for the projectile I
    think I can wind a coil of smaller magnet wire around some carbon
    fiber and then laminate around or beneath it.

    I want to understand coilgun design because I advocate making a giant
    coilgun to launch stuff into space from Earth.

    Thanks for your advice,

    Ross F.
  7. Chriz


    Aug 25, 2010
    You could just use a circuit out of a disposable camera, it basically converts 1.5v from a AA battery to 250v-330v.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day