On Thu, 16 Oct 2014 16:10:47 -0700, Jim Thompson
wrote:

Hi Kevin,

Suppose I wanted to model JUST the capacitance portion of a diode? No
DC current, etc.

The equation "fold-over" at VD~FC*VJ looks to be PITA to implement.

Maybe you know of a way to trick a full diode model into not doing its
DC thing ?:-}

...Jim Thompson

Isn't that just a nonlinear capacitor?


Version 4
SHEET 1 1096 680
WIRE 48 80 0 80
WIRE 176 80 48 80
WIRE 320 80 240 80
WIRE 480 80 320 80
WIRE 576 80 528 80
WIRE 624 80 576 80
WIRE 0 144 0 80
WIRE 320 144 320 80
WIRE 528 144 528 80
WIRE 480 160 480 80
WIRE 0 272 0 224
WIRE 320 272 320 224
WIRE 480 272 480 208
WIRE 528 272 528 224
FLAG 0 272 0
FLAG 320 272 0
FLAG 480 272 0
FLAG 528 272 0
FLAG 576 80 CAP
FLAG 48 80 RAMP
SYMBOL res 304 128 R0
WINDOW 0 49 47 Left 2
WINDOW 3 50 78 Left 2
SYMATTR InstName R1
SYMATTR Value 1µ
SYMBOL voltage 0 128 R0
WINDOW 0 68 65 Left 2
WINDOW 3 17 112 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 100 0 100)
SYMBOL e 528 128 R0
WINDOW 0 64 53 Left 2
WINDOW 3 58 85 Left 2
SYMATTR InstName E1
SYMATTR Value 1e6
SYMBOL cap 176 96 R270
WINDOW 0 -43 32 VTop 2
WINDOW 3 77 35 VBottom 2
SYMATTR InstName C1
SYMATTR Value q = x / (1+2*x)
TEXT 16 112 Left 2 ;1 V/S
TEXT 560 112 Left 2 ;1 V / F
TEXT 368 8 Left 2 !.tran 0 1 0
TEXT 8 -96 Left 2 ;Nonlinear Capacitor C:V Curve
TEXT 48 -56 Left 2 ;J Larkin August 11, 2014
TEXT 480 -96 Left 2 ;Cap is 1F at low voltage
TEXT 536 -56 Left 2 ;0.1F at 1 volt











--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com