[Boatanchors] Carbon Mic Rejuvination

[Richard Knoppow]

----- Original Message ----- 
From: "Bill Carns" <wcarns at austin.rr.com>
To: "'rbethman'" <rbethman at comcast.net>; 
<boatanchors at mailman.qth.net>
Sent: Saturday, March 16, 2013 10:51 AM
Subject: Re: [Boatanchors] Carbon Mic Rejuvination


> That last paragraph should have read:
>
> There has to be "Conservation of energy" in any system 
> ....which basically
> says there is no free lunch.  If you do not apply external 
> power - like in a
> supply to an amplifier, then a passive element like a 
> water valve, or a
> passive modulator like a carbon mic, cannot have POWER 
> gain.
>
> You can have voltage gain....like a transformer....  But 
> no power gain.  If
> you gain voltage, you lose current.
>
> Bill

    The carbon microphone DOES have a source of external 
power.  There _must_ be a source of DC. It can be a battery 
or the cathode current of a vacuum tube. In any case there 
is a power gain. One of the pre-vacuum tube attempts at 
telephone repeaters was the use of a carbon microphone 
driven by a magnetic receiver.  These did not work very well 
due to the high noise but did work.
    Now, while a valve controlling the flow of water or gas 
is not electronic it also has a source of external power. 
That can be someone's hand or an electrical or hydraulic 
actuator of some sort. In any case the amount of energy 
needed to move the valve is a fraction of the energy it may 
be controlling.  Again, its a form of amplifier.  A carbon 
microphone is, in fact, a form of valve, as is a vacuum 
tube, controlling an external source of power which can be 
substantially larger than the power applied in actuating it. 
One can use a potentiometer as an analogue, it is a variable 
resistor which is varied by a small mechanical force.  The 
electrical force carried by it can be a fraction of the 
force needed to change its value, again its an amplifier. 
No laws of nature are being violated.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com