Version 4
SHEET 1 880 680
WIRE 224 80 -48 80
WIRE -48 128 -48 80
WIRE 224 144 224 80
WIRE -48 256 -48 208
WIRE 224 256 224 208
WIRE 224 256 -48 256
WIRE -48 272 -48 256
FLAG -48 272 0
FLAG -48 80 1
SYMBOL cap 208 144 R0
SYMATTR InstName C1
SYMATTR Value Q=0.1p*x +35p*(x+log(cosh(a*(x+b)))/a)
SYMBOL voltage -48 112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PWL(0 -1 2 1)
TEXT -56 -16 Left 2 !.tran 0 2 1u
TEXT 256 -16 Left 2 !.param a=15 b=-0.25
TEXT -56 -64 Left 2 !.options plotwinsize=0
TEXT 256 -64 Left 2 ;Adjust param a and b.