[Hallicrafters] Piesoelectric effect case in point.

[rbethman]

Well, as Carl pointed out, first the proper spelling is piezo.

I can see this with quartz.  The 1950's Shure element is one big slice 
of quartz.

I'm having a problem with "ceramic"  What is the ACTUAL construction of 
"ceramic disk" capacitors?  In every application of "ceramic" materials, 
they don't work ANYTHING like quartz.

The best of my knowledge, disk caps have been mica for the dielectric.  
The silver mica migration has come up quiye a bit over the years.

Bob - N0DGN

On 1/2/2011 3:23 PM, Roger (K8RI) wrote:
>> Hi Walt
>>
>> That is interesting. I personally was never fond of ceramic disks in audio
>> circuits, especially for coupling. But I never expected that the effect
>> would be that pronounced. Thanks for the verification.
>>
> I wonder if this is truly a "piesoelectric effect" of the caps having
> developed a mechanical defect that allows the capacitance to change
> value with vibration, or mechanical shock, thus acting like a capacitor
> microphone.  The results would be the same the mechanics are quite
> different.
>
> 73
>
> Roger (K8RI)