[ARC5] Carbon cartridge replacement circuit

[hwhall at compuserve.com]

If you have an o-scope handy, connect scope leads to the mike elements & set the scope to a very lowe voltage range (e.g., millivolts per div). If it's a dynamic one (or a crystal one) you can tap on the element or talk into it & see a signal on the scope. A carbon mike won't show any voltage signal.

 

 Wayne
WB4OGM

 

-----Original Message-----
From: Roy Morgan <k1lky68 at gmail.com>
To: J Mcvey <ac2eu at yahoo.com>
Cc: ARC-5 List <Arc5 at mailman.qth.net>
Sent: Thu, Apr 27, 2017 11:52 am
Subject: Re: [ARC5] Carbon cartridge replacement circuit



J,


I have more than one microphone used in Navy planes (helicopters) in the 60's and 70's.  I am not sure if these are carbon microphones or dynamic ones (we did use little inline amlifiers at about that time with some of the lip mikes we had.)


Can you give any hints as to how to determine which is which?  Resistance maybe? One is gray and another one or two are black.  They mounted on the helmets.


Oh yes, I will look on them for some sort of nomenclature - I bet I'll find something.


Roy




On Mon, Apr 24, 2017 at 9:06 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net> wrote:


Hello all ,


I finally got this drawn up and published.
This circuit will produce up up to  about 4 vpp without clipping.
It has  more than enough gain to produce maximum modulation without yelling into the mike.
Enjoy;








https://www.mcveyelectronics.com/images/stories/pdf_files/electret_carbon_rpl.pdf

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-- 



Regards,

Roy


Roy Morgan

k1lky since 1958



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