Peter Chadwick wrote:
>When we were discussing this matter here a few weeks ago, Tom indicated
>(although I may have misunderstood him) that the the output impedance is
>a 'non dissipative resistance'.
"Resistive, but not dissipative" would be closer to the mark.
The article uses the term "impedance" in the sense of being the ratio of
voltage/current observed at a particular location. To the extent that V
and I are in phase, this impedance is resistive - but it doesn't have to
be dissipative.
There are many other examples of resistive but non-dissipative
impedances. The characteristic impedance of a transmission line is one
of them. Another example is that you can measure V, I and phase at
various locations along a transmission line, and deduce values of
impedance - but no power dissipation is taking place at those locations.
One other thought: before anybody judges this article on the basis of
personalities, don't forget the reputations of the other two authors,
namely Belrose and Maxwell.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.demon.co.uk/g3sek
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|