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Angular parallel plates capacitor

Discussion in 'General Electronics Discussion' started by seza, Aug 31, 2019.

  1. seza

    seza

    30
    1
    Nov 6, 2015
    Hi,

    I hope you good people can enlighten me on this,
    Parallel plates capacitor charge and/or capacitance calculations are well known,
    suppose one take a rectangular shaped capacitor and bend it 90 degrees into an "L"
    shaped capacitor.
    What effect that will have on capacitance and/or charge of the whole capacitor?

    thanks.
     
  2. Nanren888

    Nanren888

    114
    22
    Nov 8, 2015
    Do you have an image of this?
    So, just to make sure that I am clear on what you mean:
    You have two parallal plates, close together, separated by some small distance, forming a capacitor and you want to fold them to 90 degrees out of the plane of the plates so the plates stay the same distance apart, have almost the same areas, almost the same small separation, relative to their size. So the electric field is still between the plates, possibly affected slightly by the bend near the corner.
    Do I have it about right?
    I guess real capacitors tend to be similar, in that the plates are frequently rolled up into cylinders. In that case, I guess perhaps there is an added benefit that the outer surfaces of the twop-plate capacitor become close to their other plate on the next turn.
     
  3. seza

    seza

    30
    1
    Nov 6, 2015
    Spot on - Nanren88,
    that is what I am talking about,
    in some research papers they refer to "edging" effect which - I believe - is the
    extra field strength at the edges and corners?
     
  4. hevans1944

    hevans1944 Hop - AC8NS

    4,231
    1,995
    Jun 21, 2012
    To determine electrical field edge-effects requires a calculus not often seen in these forums. What are you trying to DO? Why is bending the parallel plates important to you? How much math are you prepared to learn (or have already learned) to set up and solve the equations necessary to calculate field strength in the presence of edge effects? Are you perhaps thinking of applying a hinge to one edge of your parallel plate capacitor in the hope that the plates attached to the other side of the hinge will somehow vary the capacitance as the plates are rotated about the hinge? If so, let me assure you that the effect (if any) will be negligible. The only things that appreciably affect the capacitance of a parallel plate capacitor are (1) the separation between opposite plates, (2) the dielectric material between opposite plates, and (3) the projected area of the smaller plate upon the larger plate, neglecting fringing that occurs at the edges of the smaller plate.
     
  5. Harald Kapp

    Harald Kapp Moderator Moderator

    9,304
    1,888
    Nov 17, 2011
  6. seza

    seza

    30
    1
    Nov 6, 2015
    Thanks - for your input,
    I am now putting this idea to rest ...
    another idea instead on a different thread.
     
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