[Boatanchors] Microphones

[Ron Youvan]

   Glen Zook wrote:

> 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

   Actually the transformer in telephones is the anti-side tone transformer, used to reduce your 
voice in your earphone, to make you talk louder.
-- 
    73 Ron KA4INM - All E-mail sent to this address shall linger in the Google cloud forever!