On Tue, 6 Apr 1999 10:48:06 +0100 Peter Chadwick
<Peter_Chadwick@mitel.com> writes:
>
>Something I don't understand - maybe Carl or Rich or Jon can explain.
>
>If I take an inductor (start with a 'perfect' inductor) and put a
>resistor
>in series with it, at LF it looks like the inductor isn't there. If I
>make
>the inductor out of resistance wire, it still looks like a resistor.
>
>Now increase the frequency. Inductive reactance rises, and the Q,
>given by
>2*pi*F*L /R increases, eventually becoming infinite at infinite
>frequency
>(OK,
>3-500s don't have any gain there!) So I have a series inductive
>reactance
>with Q increasing with frequency.
>
>Now take the coil, wind it out of silver tape if you like, and put a
>33 ohm
>resistor across it. At this stage, it's a perfect resistor. At LF, the
>low
>reactance of the coil shorts out the resistor, but as the frequency
>rises,
>so does the coil reactance. Because it's a parallel circuit, the
>impedance
>tends asymptotically to 33 + j0. Even a practical resistor will tend
>that
>way. As Q is Rp/1*pi*F*L, the Q is falling with frequency - in fact,
>it will
>have a maximum value at VLF.
>
>If I understand Rich's argument, the Q of a paraistic suppressor
>should fall
>with increasing frequency. So there seems to me to be an anomaly -
>from the
>above argument, an L-R shyunt circuit is indicated.
>
>can someone explain?
>
>73
>
>Peter G3RZP
This goes back to Richs so called " grate (sp) debate" with Tom, Wes and
others.
Rich seems to enjoy being the odd man out.
Once I see any major amp manufacturer, ham or commercial/industrial use
voodoo suppressors I may consider the slim possibility that they do
"something".
For now Rich can sell what he wants to whomever he wants, hams are known
to buy anything with no clue.
73 Carl KM1H
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]
--
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
|