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Homemade Coil Help

Discussion in 'General Electronics Discussion' started by philipk, Dec 28, 2017.

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  1. philipk

    philipk

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    Dec 28, 2017
    Hi Everyone, I'm a newbie here. I have a project I want to get back up and running.
    It's a "shock box" we the make for electronics class in middle school (late 70's) from scratch.
    I want to get it working again. The coil in it has primary and secondary windings and I've tested it
    with a meter everyday I can think of. The thing has sat in a drawer from 40 years. Could both sets of windings gone bad?
    Any help would be greatly appreciated! Thanks! Kevin
    P.S. attached are 2 crude photos
     

    Attached Files:

  2. kellys_eye

    kellys_eye

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    Jun 25, 2010
    It's unlikely the windings have gone bad. Have you fitted batteries and tested it?
     
  3. philipk

    philipk

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    Dec 28, 2017
    No... I thought I'd test the coil first then put a battery in it.
     
  4. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    I thought you were gonna dig out an old Ford spark-plug "coil" which used a magnetically-actuated interrupter to rapidly break the current in the primary winding. The rapidly collapsing magnetic field induced a large voltage in the secondary coil. The whole contraption was nicely packaged in a wooden box with well-made finger-joint corners. Two "button" contacts about the size of a dime were connected to either end of the secondary and mounted to the top of the wooden box. A six-volt lantern battery served nicely to energize it. And, yes, it would deliver a very nasty shock with a fresh battery.

    With the litigious nature of today's society, I would be afraid to revive, much less actually use, such a device.
     
  5. philipk

    philipk

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    Dec 28, 2017
    A "D" size battery didn't make it work.
     
  6. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The arrangement of wire (paper clip?) needs to be set such that movement causes the circuit to be made/broken as it is the interruption of the supply that causes the large back-emf in the coil to deliver the 'shock'.
     
  7. philipk

    philipk

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    Dec 28, 2017
    All the connections look like they are tight and/or working properly.
    Next step?
     
  8. Bluejets

    Bluejets

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    Oct 5, 2014
    I remember seeing one of those in Dad's shed.
    One of the reasons we used to find somewhere else to be when he would say "just come and hold this for me for a second".....

    For the jigger mentioned above we used to use a realy coil and wind a primary over the existing....all fitted in a case the size of a cigarette pack that one would "leave" lying around in wait....:eek:.....:D
     
  9. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    Here's a picture of the Model T Ford spark coil, modified for use as a spark-gap transmitter with the addition of the three Fahnestock clips, presumable two for the spark-gap wires and one for the antenna connection. Don't try this at home!

    [​IMG]

    Above image copied from this website page. You can get the same "shocking" effect by connecting a D-sized cell with bare (un-insulated) copper wires soldered to an inductor. Connect the two bare wires from the inductor to a D-cell by holding the connecting wires in your bare hands and touching the ends of the wires to the cell terminals. When you remove the wires from the D-cell you will feel a shock from the inductor, mild or strong depending on how big the inductor is, the freshness of the D-sized cell, and the sweat on your fingers. For more adventure, use a 6 V lantern battery instead of a single D-sized cell. A 10 H inductor will provide a suitably nice "kick" when you disconnect the wires.

    Still greater adventure can be found if you construct an induction coil with a movable, sliding iron cover to "short out" the magnetic field of the coil. The high-tension end of the coil is connected electrically to a pivoting conductive handle that moves the iron cover. Only the strongest and bravest will be able to rotate the handle far enough to completely remove the iron cover from the coil and deliver the maximum shock potential. The other end of the coil is attached to a fixed conductive handle to allow the circuit to be completed through the player's body, including both arms and the chest and (presumably) the heart. I "played" with a commercial version of one of these at a roller skating rink near my grandparents house in Morristown, TN, in the 1950s, similar to the picture shown below:

    [​IMG].
     
    Last edited: Dec 28, 2017
  10. philipk

    philipk

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    Dec 28, 2017
    How do I test the primary and secondary winding properly to make sure the coil is or isn't my problem?
     
  11. duke37

    duke37

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    Jan 9, 2011
    Measure the resistance of the primary and secondary to check for continuity. This will not enable shorted turns to be detected. This can be done with an inductance meter which are now quite cheap from China. Read Hop's #9 to try to get a weak shock.
     
  12. philipk

    philipk

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    Dec 28, 2017
    Thanks duke37! I'll try to test it with an inductance meter.
     
  13. Wiginometry

    Wiginometry

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    Nov 29, 2017
    Must... try at... home. Alright I understand completely I'm going to be having a lot of fun!!!!!
     
  14. Wiginometry

    Wiginometry

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    Nov 29, 2017
    If nothing else if you don't have an inductance meter handy and you order one if you have all the parts necessary you could always clone it.
     
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