PSN-L Email List Message

Subject: Re: S-G construction
From: ChrisAtUpw@.......
Date: Wed, 26 Jan 2000 06:41:58 EST

In a message dated 25/01/00 18:37:12 GMT Standard Time, 
randallpratts@.............. writes:
<<  I'm looking at the S-G construction notes on the PSN file.  Does anyone 
 advice or experience with component substitution,  operation on 12 volts
 instead of the 16 volts shown or other general comments?  What about using
 the XTAL from a TV picture tube which I think is about 3.49 MHz? 

    You need two L/C tuned circuits + diode rectifiers + smoothing capacitors 
for your two position sensor plates. These have to resonate with a stabilised 
amplitude crystal oscillator drive voltage on the central plate. The devices 
that Larry sells are already set up and tuned.

    If you don't have quite a bit experience of electronics (if you were 
completely confident of your abilities, would you ask?), buying the ready 
made sensor plates etc. would give you the certainty of success. The S-G 
circuit in my copy of the notes operates on +/- 12 V. The new design is a 
considerable advance on the original Scientific American circuit, which used 
16 V supplies. Have you considered it?

    Regards Chris


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Larry Cochrane <cochrane@..............>