[ARC5] More Condenser/Capacitor Trivia

[Fuqua, Bill L]

   Condensers were called just that and used before the discovery of radio waves.
In fact the transmitter that Hertz built used a condenser, induction coil and interrupter.
  Induction coils go back to at least the 1870's. Well before the invention of the Tesla coil.
Tesla only did it in a more impressive way and bigger. 
  Michelson and Morley disproved the existence of the ether about the same year that
Hertz discovered radio waves. It was well known that light was waves and it was assumed that
it had to propagate thru some material and that was given the name ether. 
  Electrical Resonance was well understood before 1890. 
   Hertz's grant was to determine if the virtual current thru the dielectric of an condenser created a
magnetic  field, I don't know if he ever got around to doing that since he had gone off into a completely
different direction. 
   He also discovered the photo electric effect, by accident and considered it an annoyance. 
One day he discovered that his receiver which used a well calibrated arc gap was arcing at a lower
voltage than it should, he later determined that it was due to the UV light coming thru a window.
It is often called the Hertz effect.
73
Bill wa4lav

________________________________________
From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Leslie Smith [vk2bcu at operamail.com]
Sent: Sunday, February 21, 2016 11:54 PM
To: arc5 at mailman.qth.net
Subject: Re: [ARC5] More Condenser/Capacitor Trivia

                                  Units of capacitance.

The (rather small) library at Westlakes Amateur Radio Club has a book
published by the British Navy - aka "The Admiralty".
In the discussion of "condensers" it gives the unit of capacitance as
"the jar".
I have no idea about the relationship between this unit and the Farad
(or micro-Farad).

I understand the idea of "condenser" comes from the understanding that
radio waves must travel in a medium, and that "the medium", (the ether)
could be trapped (or condensed).  This notion of "trapping" the ether in
a vessel (a condenser) led to the name.  This is an interesting concept!

I will read further postings on this topic with interest, since all
"command" radios have many "condensers", some variable.

Further, I'd like to point out to all the other list readers that the
Westlakes Radio Club MUST be an excellent organization - to have such an
authoritative book in the club library.   Our club lies on the Western
side of Lake Macquarie, hence the name.  Visitors to the region will be
welcome at the club.

   73 to all (including those who have condensers in their radios etc)
   de Les Smith
   vk2bcu at operamail.com

                          R   ж-ж-ж             и-и-и             ж-ж-ж
                           Я

On Mon, Feb 22, 2016, at 13:11, Dennis DuVall wrote:
> Did a quick check in my library.  They were “condensers" in Terman’s 1937
> edition.  The RCA "Radiation Designer’s Handbook" used both terms in it’s
> 1941 edition.  My college “Radio Electronics” textbook (1956) used
> “capacitor.”  The ARRL Handbooks were still using “condenser" in 1952 but
> had switched to “capacitor” by 1960.  "The Radio Handbook"  (Editors and
> Engineers), however,  was using  “capacitor” as early as 1947.
>
> Dennis D.  W7QHO
> Glendale, CA
>
> ***************
>
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