January 2011.

Advice on reading “The End of Electric Charge and Electric Current as we know them” Part 1 January 2011 and Part 2 February 2011 from Electronics World.

Ivor Catt.

It is important to not get bogged down in the mathematics, which could have been omitted. Initially, skim through the maths in the second column, which merely proves that a signal travelling down a coaxial cable sees ahead 50 ohms and travels at the speed of light for the dielectric. Avoid the third column; “Crosstalk in Digital Systems”, which is merely an extension of the previous maths, but deals with more conductors and shows that whereas in a coaxial cable a single impedance and single velocity is permissible, in the case of more wires, more “modes” are possible. The mathematics is very similar to what went before, but more complicated, now involving not only self inductance, but also mutual inductance. Try to assume, initially, that complicated mathematics proves two impedances and two velocities rather than only one in the case of coax.

At this point, look at the photographs, Figure 3 for visual proof of the two “modes”, and so bypass the mathematics.

Note that Figure 4 is an idealised version of Figure 3. A plane wave front is advancing at the speed of light guided by the conductors. It begins at the third trace, then advances 3 metres to the second trace, then another three metres.

Figure 4 diagramatically clarifies the waveforms.

I very much need comment from you as to your expertise, and how difficult you find the article. Send comments to ivorcatt@live.co.uk . Suggestions for improvement would be valuable.