Talk:Ivor Catt/Archive 14

message: Everyone seems to be Catt-napping! Why is this?--Light current 22:50, 15 April 2006 (UTC)
replies: text: Well, the archiving struck, and your last comment seemed to suggest that you didn't want to discuss the several very serious flaws in the Dec '78 Catt et al article, which I believe are the key to understanding the stand-off between Catt and "orthodox science". -- Kevin Brunt 21:50, 19 April 2006 (UTC)

message: Copied from archive #13--Light current 00:50, 20 April 2006 (UTC)
replies: text: I'm familiar with the article. I dont think your argument regarding angles is at all relevant to Catts analysis which in my view is substantially correct. If there is a mismatch between the feed and the Z0 of the cap, you get reflections. What's the problem? BTW a capacitor is sometimes made from separated plates wound ito a cylinder. They are all transmission lines!--Light current 01:57, 21 March 2006 (UTC)

text: Kevin. Its your turn!!--Light current 00:52, 20 April 2006 (UTC)
thread_title:  The opening 

message: OK. Let's start by noting that I have no quarrel with the analysis of the voltage waveforms observed on a "charging transmission line." However, in spite of the assertion in the article, this does not prove that "a capacitor is a transmission line." In fact it only demonstrates the converse, that a transmission line is a capacitor; specifically a long capacitor that is so thin that it can be considered to be a one-dimensional line. The analysis cannot be extended to the two-dimensional case of a "real" capacitor, because it cannot explain how (for example) a circular wavefront spreading out across a rectangular plate would reflect off the far edge. The 1-D analysis can only have the voltage front returning the way it came; it is far more likely that what really happens is similar to an optical reflection with the angle of incidence being equal to the angle of reflection.
Basically, the analysis by Catt et al is incomplete. The leap from 1-D to 2-D requires additional work which they have not done, and which they undoubtedly will not do, because it would require the admission that the equations for the characteristic impedance and velocity of propagation for a TL are not derived experimentally (as they appear to imply), but are a theoretical solution of the "Laplacian" Telegraphers' Equations. Viewed from the "other direction", the Telegraphers' Equations provide the way to explain why the behaviour of a voltage step travelling along a TL is dictated by the inductance and capacitance of the TL. Furthermore it is relatively trivial to generalise the TE's, not only from a 1-D line to a 2-D surface, but also to situations where the inductance and capacitance are not uniform across the surface, or even are not constant over time. But Catt et al believe that the Telegraphers' Equations have a "spurious high-frequency cutoff". (Is this because they avoid considering the implications of the resistance of their conductors?)
The article also claims that "This model does not require use of the concept of charge." This is more than a little difficult to support, since the model does use the concept of impedance which is a statement of the relationship between voltage and current, and so is inescapably based on the concept of charge itself! -- Kevin Brunt 19:26, 20 April 2006 (UTC)
thread_title:  Kevins opening move 

message: It would appear that you have not read Catts article very closely. He descibes the disc capacitor as being made up of a number of sectors of the disc all in parallel. Each sector can be considered as a // plate capacitor of varying (decreasing)Zo as you travel toward the perimeter of the disc. A circular wave front can be split into a large (infinite) number of straight line wave fronts each travelling down its own tapering transmission line. I see no problemo!!--Light current 00:28, 21 April 2006 (UTC)
replies: text: This is another special case - the circular disc is highly symmetric. At any point on the edge of the disc the tangent to the edge is perpendicular to the line between the point and the centre of the disc. Consequently, the issue of non-perpendicular reflection does not arise. This is just more of Catt et al avoiding the issue. -- Kevin Brunt 12:22, 21 April 2006 (UTC)

text: For all of Catt's assertions, the voltage anywhere on the plate of a capacitor is a measure of the amount of charge there; an advancing voltage front is equally an advancing charge front. In a TL, because the front is advancing evenly across its width, any tendency to flow "sideways" will be self-correcting. However, if the front encounters an "edge" obliquely, so that the interaction does not occur simultaneously across the width of the front, the "symmetry" is destroyed and a 'y' component to the motion of the front is introduced. In terms of the "TL model" the voltage step at the open end is not constrained to travel back the way it came, but can spread out into any adjacent area with less charge per unit area (and therefore is at a lower voltage.) At this point the adjacent TLs are interacting with each other and any analysis based on parallel TLs collapses in a heap. -- Kevin Brunt 23:21, 21 April 2006 (UTC)
thread_title:  3. Capacitor with disk type plates