Charles:

Your schematics don't show any capacitors on the regulated supplies.  LM78xx
and 79xx regulators are notorious for oscillating if they have no output
capacitors.  For best results you should have 10uF or more on each power
supply for each circuit block, plus 0.1uF caps for each IC.  At higher
frequencies it gets more complex, but this should work fine at seismic
frequencies.

	Keith
 

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Charles Staniger
Sent: Wednesday, April 12, 2006 11:45 AM
To: psn-l@..............
Subject: Power Supply Question?

Hello Everyone,
 I am a junior in college and last summer I build a
seismograph for a school project.  The amplifier and filter
work great together, but when I connect the power supply to
the amp. and filter the system doesn't work.  At the end of
this email I have provided the URL's for the schematics of
the amplifier, filter, and the power supply.  
 Currently, the amplifier and filter are using a quad
power, power supply, but I would like to build my own power
supply.  My question is, Does anyone know of any power
supply schematics that would work with my amplifier and
filter?  


Amplifier and Filter:
 http://users.viawest.net/~aloomis/seisfilt.htm

Power supply:
http://users.viawest.net/~aloomis/seisprea.htm

Sincerely,

 
Charles Staniger
President, Carthage College Habitat for Humanity Chapter


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