Hi John,


I've posted some schematics on my web site as well.


Amplifier/Filter circuit from Chris Chapman:


http://jclahr.com/science/psn/amp_filt/


Linear Variable Differential Transformer sensor from Chris Chapman:


http://jclahr.com/science/psn/chapman/lvdt/lvdt1.html



http://jclahr.com/science/psn/chapman/lvdt/lvdt2.html


Folded pendulum seismometer electronics package from David H.
Youden:


http://jclahr.com/science/psn/youden/electronics/fpelectronics.html



Basic optical sensor circuit for a self-centering SG
type pendulum system 

from Chris Chapman:


http://jclahr.com/science/psn/chapman/photo_detect/


Micorphone amplifier for use with gunshot location system using 

a TLE2426ILP to avoid need for dual power supply from Fred Fischer :


http://jclahr.com/science/psn/gunshots/of93221/fig1.gif


Is the use of a 1/2 rail virtual ground a good idea for seismic 

amplifiers?  What is a newer part for this purpose?  See:

<
http://www.digikey.com/scripts/dksearch/dksus.dll?KeywordSearch?Mpart=TLE2426ILP&site=us
>


Symmetric differential capacitive sensor from Randall Peters:


http://jclahr.com/science/psn/capacitive/


Folded pendulum design from Brady Romberg's team at the

Colorado School of Mines:


http://jclahr.com/science/psn/epics/reports/folded/


Cheers,

John Lahr




At 02:42 AM 3/1/2005, you wrote:

"Steve Hammond"
<shammon1@.............> wrote:


> Hi John, Hi Chris and others,

> You can find what many consider to be the original PSN amp
design

> at

http://pw2.netcom.com/~shammon1/equip.htm#Plans in the right
column.

> In my document files,  I also have an older design done by Jan
Froom

> which dates back before 1989 which includes a 12-bit A/D. 

> Pete Row designed the amp and filter found on the website 

> and freely gave it to the members of the PSN group in 1990 

> at one of the first PSN meetings we held.

(snip)

> Below that, on the same web page, you will find another design 

> which came from Sean Morrissey. Sean has passed as may know 

> and was also a world class designer. I have been using Pete's
design

> for 15 years and it is easy to build and diagnose when an op-amp
fails.

(snip)


Thank you, Steve, for this information.  

I will review these amplifier and filter designs, in detail, 

including all filter responses.


Are you interested in seeing my critique of these when I get to
that?


I am sure my design will steal

from them, though I think I might be able to slightly improve 

upon some aspects, based on a quick look.  

I will make available to the group anything that I design, 

including a parts list, theory of operation, and schematic. 



If you have any other schematics in emailable form that you would 

like me to consider, you may email them to me at jpopelish@.........

I am not worried about this address appearing in public, 

since it is what I have used on usenet for a few years.

I often tutor, there, on sci.electronics.basics.


-- 

John Popelish

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