Version 4
SHEET 1 880 680
WIRE 448 -64 320 -64
WIRE 544 -64 448 -64
WIRE 448 -32 448 -64
WIRE 320 -16 320 -64
WIRE 448 80 448 32
WIRE 320 96 320 64
WIRE 320 96 192 96
WIRE 192 144 192 96
WIRE 320 176 320 96
WIRE -272 256 -400 256
WIRE -144 256 -192 256
WIRE 192 256 192 224
WIRE 192 256 48 256
WIRE 272 256 192 256
WIRE 544 272 544 -64
WIRE 192 304 192 256
WIRE 112 320 48 320
WIRE -400 352 -400 336
WIRE -144 352 -400 352
WIRE 112 416 112 320
WIRE 192 416 192 368
WIRE 192 416 112 416
WIRE 320 416 320 272
WIRE 320 416 192 416
WIRE 544 416 544 352
WIRE 544 416 320 416
WIRE -400 480 -400 352
WIRE 320 496 320 416
FLAG 320 496 0
FLAG -400 480 0
FLAG 448 80 0
SYMBOL res 176 128 R0
SYMATTR InstName R1
SYMATTR Value 87k
SYMATTR SpiceLine tol=1
SYMBOL voltage 544 256 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR InstName V1
SYMATTR Value 450
SYMATTR SpiceLine Rser=5
SYMBOL zener 208 368 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value BZX84C12L
SYMBOL nmos 272 176 R0
SYMATTR InstName M1
SYMATTR Value SPA11N60C3
SYMBOL voltage -400 240 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 12 1 0.0005 0.0005 0.2 2)
SYMATTR SpiceLine Rser=0.01
SYMBOL res -176 240 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 212R
SYMBOL Optos\\4N28 -48 320 R0
SYMATTR InstName U2
SYMBOL res 304 -32 R0
SYMATTR InstName R2
SYMATTR Value 990R
SYMATTR SpiceLine tol=1
SYMBOL cap 432 -32 R0
SYMATTR InstName C1
SYMATTR Value 1.8mC
TEXT -434 520 Left 2 !.tran 0 10 0 0.0005