Topband: Displacement current

[Robert Brown]

Friends in Radio Land

The electromagnetic variable D and the displacement current         
density dD/dt were introduced in Maxwell's Equations so as to make 
current continuous around a circuit containing capacitors.

The beauty of the idea is that it compliments Faraday's Law - 
time-varying magnetic fields (dB/dt) generate electric fields (E) -
by having time-varying displacement (dD/dt) generating magnetic      
fields (B).

As a result, Faraday's Third and Fourth Equations may be combined 
to obtain an equation predicting  electromagnetic wave motion, as 
observed by Herz and the basis of all of ham radio.

Just think of an antenna and its ground system as a discrete component, 
a big capacitor, and RF current is continuous around your output circuit.
 
73,

Bob, NM7M