The Catt Question


Animated Catt Anomaly           Book          IEE Paper


The Question

Traditionally. when a TEM step (i.e. logic transition from low to high) travels through a vacuum from left to right, guided by two conductors (the signal line and the 0v line), Figure 5, there are four factors which make up the wave;

- electric current in the conductors

- magnetic field, or flux, surrounding the conductors

- electric charge on the surface of the conductors

- electric field, or flux, in the vacuum terminating on the charge.

The key to grasping the anomaly is to concentrate on the electric charge on the bottom conductor. During the next 1 nanosecond, the step advances one foot to the right. During this time, extra negative charge appears on the surface of the bottom conductor in the next one foot length, to terminate the lines (tubes) of electric flux which now exist between the top (signal) conductor and the bottom conductor.

Where does this new charge come from? Not from the upper conductor, because by definition, displacement current is not the flow of real charge. Not from somewhere to the left, because such charge would have to travel at the speed of light in a vacuum. (This last sentence is what those "disciplined in the art" cannot grasp, although paradoxically it is obvious to the untutored mind.) A central feature of conventional theory is that the drift velocity of electric current is slower than the speed of light. [Published in Electronics & Wireless World sep84, reprinted sep87. For further information on the Catt Anomaly, see letters in the following issues of Wireless World; aug82, dec82, aug83, oct83, dec83, nov84, dec84, jan85, feb85, may85, june85, jul85, aug85.]


Pepper FRS and Dr. McEwan contradict each other in their answers. See