Hello Mr. Chapman;

I often wonder about this.

Once I spoke with an Engineer
who said whatever he did
to one side he also did to another.

He also said he never gets the gain he is looking for.

But if you look at the diagrams for this kind of circuit,
they never show the capacitor on the + side.

Please, are you able to explain ,in layman terms,
why this capacitor is necessary ?

I understand some engineering terms
but not how to implement them into
circuitry. My Electronics education,
although ok for Military operations/maintenance work,
is lacking for civilian type stuff.

Welcome back Mr. Chapman,
it has been a long time since I have
seen you posting.

Best Regards,
geoff

-----Original Message----- 
From: Christopher Chapman 
Sent: Tuesday, December 14, 2010 12:16 PM 
To: psnlist@.............. 
Subject: Re: Station GVA current Schematic for low resistance Geophone SPZ (HS10) 



Subject: Station GVA current Schematic for low resistance Geophone SPZ (HS10)


t completed a crude N=8 Gain x1 LPF with a knee at 10Hz (about) 
and my first try went well. I think this is BUTTERWORTH. 

http://gmvoeth.home.mchsi.com/LATEST/CIRCUIT/GVA_CIRCUIT.HTML 

Hi Geoff,


    Your circuit is faulty. You need an additional 2 muF capacitor across R1.B

Chris Chapman

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