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Electro magnetic Inductor

Discussion in 'General Electronics Discussion' started by spk, Mar 19, 2014.

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  1. spk

    spk

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    Feb 28, 2014
    Hi everyone for my science fair project I need to generate an electromagnetic field, so I'm searching inductors on the web, so from what I understood a teroidal inductor wouldn't be good for my project but a iron core one would be better so, I'd have 2 capacitors of 1200uf and 350v, so maybe someone know which type of inductor I should take and how many Henry should I use, I'm sorry I'm a little bit lost but thank you so much for you help
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Start from the beginning.

    You want to generate an electromagnetic field -- what for? how strong does it need to be?

    A toroidal inductor makes a magnetic field, but it's all inside the toroid. If you have an air core you can place something within it, but not if you use an iron core.
     
  3. spk

    spk

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    Feb 28, 2014
    Hi Steve, it's to show the dangers of the electro magnetic pulse, so I use an old disposable camera with 2 1200uf capacitors, from what I saw on the web the toroidal inductor wouldn't let me a lot of place to put something, so it wouldn't need to have an huge radius, (it would be even better if it's small so I wouldn't risk to burn up the phone of everyone in the room during the science fair) but I'd like to be able to fry an old calculator or phone.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,449
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    Jan 21, 2010
    And are you sure that's going to be enough energy?

    What research have you done on EMP that indicates this will work?

    How are you going to protect sensitive electronics (say the pacemaker that may be inside the chest of some passer by)?

    If you're stuck, I can give you some things to google for.
     
  5. spk

    spk

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    Feb 28, 2014
    With internet and people who made the same projects I saw that they were having some results with capacitor of 300uf max so I hope I could get minumum the same result than them, but my problems right now are the inductor that I cannot find/make.

    With the help of my physics teacher I already made a bobine that let me restart (sometimes if I'm lucky) an old half broken DS or to make an old calculator bug (writting random things and other).

    For the protection, actually my project doesn't have a radius bigger than 20cm (metric system sorry ^^) if with another inductor I get a bigger radius, I'll have to make all the experiment at home and project the video during the science fair, I've already talked with the teacher that organize the sceince fair about the security measure.

    Yeah, I'd like you your help for this, I have 2 capacitor in parallel, so with a total of 2400uf and 350v AC, I'm wondering which type of inductor I should choose to have an external magnetic field, powerful enough to have something I could present. And I'm wondering about something, the more Henry there is in a inductor, the powerful the magnectif field will be but if there's too much Henry on the inductor and not enough energy, wouldn't I have a really small magnetic field or not? I'm a bit lost on this, I hope you could help me, thank you Steve
     
    Last edited: Mar 19, 2014
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    But were they generating EMP? I guess it's somewhat an issue of semantics.

    What did you discover when you looked for a definition of EMP?

    What is a "bobine"?

    How are you keeping the effect within this radius?

    Only apologize if you're not using it.

    What effect do you think a greater radius has (I assume you're talking about the radius of the coil)?

    Are you sure they're rated for 350VAC? How big are they?

    Have you researched what determines the strength of the magnetic field?

    That's not necessarily true

    Yep, you're lost.

    One thing is the measurement unit Henry. It's a unit, like the metre. Saying you have too much Henry on the inductor is like saying you have too many metre on a string.

    A string can be too long, and a coil can have too much inductance. Length is measured in metres, inductance in Henries. And 1H is a *HUGE* amount of inductance for most practical purposes. Typically it's like measuring your height in kilometres.

    What you need to do is to figure out how the construction of a coil influences the magnetic field.

    Then you need to consider whether you want a static magnetic field or something different.

    Then you need to look at what happens when you discharge a capacitor into a an inductance. Is there any way of determining how this might affect the generated magnetic field?

    Then you need to determine what combination of capacitance, voltage, inductance, and coil construction are going to give you the best effect.

    Finally, you should research Faraday cages and build one around your project. Even if it turns out to be just for show, it will make people feel a lot safer approaching it with the fairly ubiquitous electronic devices that exist today.

    Here is a quote for you:
     
  7. spk

    spk

    7
    0
    Feb 28, 2014
    -But were they generating EMP? I guess it's somewhat an issue of semantics.

    Yes it was EMP generator, charging a capacitor and discharging it in a coil

    -What did you discover when you looked for a definition of EMP?

    -Oh EMP is just the pulse ( I wrote this message at 3 am for me)

    -What is a "bobine"?

    I was talking about a coil sorry

    -How are you keeping the effect within this radius?

    I cannot control that, it's why I won't use it during the science fair if the radius is too big.

    -Only apologize if you're not using it.

    Ok now I don't know if I'm on an US forum or a UK one or something else ^^

    -What effect do you think a greater radius has (I assume you're talking about the radius of the coil)?

    I think that a greater radius would give more effect on every electronics things that are on the center of the field

    -Are you sure they're rated for 350VAC? How big are they?

    Yep, 350VAC I bought them from ebay to replace the 120uf that was inside the camera

    -Have you researched what determines the strength of the magnetic field?

    I tried a lot of research, I had result about the number of spire, the intensity, the lengh of the coil and a lot more of parameters



    Thank you a lot for all of this, I have to go to school, I won't be able to write more but I will look for all of this and write what I found and what I can do more, I've already had a some result with my EMP, I'm just trying to make them more flagrant, and I was already going to build a faraday cage, thank a lot Steve
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,449
    2,809
    Jan 21, 2010
    I think you should Google EMP. It covers a wide range of phenomena. Perhaps you need to be a little more specific.

    OK. That makes sense. Was that a translation issue?

    The point is you simply *can't* control that. For safety, I would recommend you shield your apparatus. Do it anyway, if only to remain legal.

    You're on the internet. Whilst this site has a .com address and is run by someone from the UK, I'm in neither of those places, and neither are most of the moderators and many of the members. Pretend you're talking to the world, because you are.

    Actually the opposite is true. And this is why you need to do some research so you understand what you're doing.

    I think you better post a picture of them. Are you sure they don't have a stripe on one side with negative signs on it (or similar).

    And you didn't specify the size. If they're about 1/15 of a cubit long and about 1/60th of a light nanosecond in diameter, I'd say they're polarized (DC) capacitors. (Oh, that's 3cm long by 1cm diameter) :D

    You need to be able to at least quantify the relative effect of the number of turns, the diameter, and the current. What does doubling or halving these do?

    The important thing for you right now is to be very sure you have non-polarized capacitors. Discharging polarized capacitors into an inductor could result in failure of the capacitor. At the voltage you're talking about, that could happen with a bang.

    Understanding the issues with capacitance and inductance and how they react when one is discharged into the other will allow you to determine (or at least estimate) the peak magnetic field, and the frequency of the ringing.

    Knowing these things, or at least having an understanding of them will help you get the most effect and may even allow you to understand a simple thing you can do to demonstrate something being destroyed by the pulse. It my be far more "sciencey" than making a few random numbers appear on a calculator.
     
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