Xref: utzoo sci.research:1529 sci.electronics:17951
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!wuarchive!mit-eddie!uw-beaver!ubc-cs!sol.UVic.CA!face!shankar
From: shankar@face.UVic.CA (P.S.Shankar.)
Newsgroups: sci.research,sci.electronics
Subject: Variable Capacitor in SPICE
Message-ID: <1991Feb21.223126.15937@sol.UVic.CA>
Date: 21 Feb 91 22:31:26 GMT
Sender: news@sol.UVic.CA
Distribution: na
Organization: University of Victoria, Victoria, BC, Canada
Lines: 33
Originator: shankar@face
Nntp-Posting-Host: face.uvic.ca


   I am trying to simulate what is essentially a RC circuit using SPICE.  I am using
   Spice 3.0 C, although I can use IG-SPICE if i need to.  I need to put in a few
   capacitors, whose values depend on the voltages on them, all of which are 
   typically time-varying. More precisely, i need to simulate capacitors which vary
   as

                                  k1
                   C =        ------------
                               k2 - k3.C.V

   where k1, k2 and k3 are constants and the C and V are the capacitor and 
   the voltage values associated with the capacitor itself.  Alternatively,
   this can be written as 
                                       
                             c1    c2   __________
                       C =  --- + ---- \/(c3 - V )
                             V     V


    I have tried to go through the available built-in utilities and functions but
    cant seem to find one, close enough to help me on this one! 
    If any of you spice wizards out there have a clue regarding this, 
    please email me ( or post it on the net...).  


    Thanks Much.

     
-- 
Shankar S Pennathur,			SCUD: Signature Currently
Department of Electrical Engg.,		      under development!!
UVic, Victoria, BC,Canada V8W 3P6               (604)-477-0381


Brought to you by Super Global Mega Corp .com