[Boatanchors] Microphones

[Richard Knoppow]

----- Original Message ----- 
From: "Glen Zook" <gzook at yahoo.com>
To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>; 
<W4AWM at aol.com>; <bluegrassdakine at hotmail.com>; 
<boatanchors at mailman.qth.net>; <boatanchors at theporch.com>; 
<collins_radios at yahoogroups.com>
Sent: Sunday, October 14, 2012 8:36 AM
Subject: Re: [Boatanchors] Microphones


Actually, carbon microphones don't require a transformer in 
tube type equipment. There are all sorts of examples in 
amateur radio equipment and in commercial FM two-way 
equipment where the carbon microphone feeds the 1st audio 
amplifier as part of the grid resistor or in series with the 
cathode.

Even with solid-state equipment, transformers are not 
needed. But, there is a requirement for a DC voltage to be 
present.

In telephones, a transformer was used in many applications. 
However, the earliest telephones did not use a transformer.

Glen, K9STH

      That's true and my error. A carbon microphone can be 
used with just a resistor in series or it can be in any 
circuit with current flowing. I had forgotten about 
applications where its in the cathode circuit of an 
amplifier. I've done this so I don't know why I forgot it.


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