Ivor Catt's Web
The Catt Question




Traditionally. when a TEM step (i.e. logic transition from low to high) ( Figures 3, 4, 5 from Electromagnetism 1 ) travels through a vacuum from left to right, guided by two conductors (the signal line and the 0v line), there are four factors which make up the wave;

- electric current in the conductors i
- magnetic field, or flux, surrounding the conductors B
- electric charge on the surface of the conductors +q , -q
- electric field, or flux, in the vacuum terminating on the charge (Figure 2), D

Signal wire



Animation by Eugen Hockenjos © :)0i 2000


The key to grasping the question is to concentrate on the electric charge -q on the bottom conductor. The step advances one foot per nanosecond. Extra negative charge appears on the surface of the bottom conductor to terminate the new lines (tubes) of electric flux D (figure 2) which appear between the top (signal) conductor and the bottom conductor.

Since 1982 the question has been: Where does this new charge come from?

Sir Michael Pepper, Knighted "for services to Physics", says it comes from the south.

Nobel Prizewinner Professor Josephson say it comes from the west.

Accredited experts line up, half behind Pepper (Southerners) and half behind Josephson ( Westerners ).

Professor Martin Rees, President of The Royal Society, may or may not do something about it.

For further information on The Catt Question, see
  • letters in the following issues of Wireless World; aug82, dec82,
    aug83, oct83, dec83, nov84, dec84, jan85, feb85, may85, june85, jul85, aug85
Historic ; Faraday's Law  

See the book about it.

May 2009 in "Electronics World"