Version 4
SHEET 1 880 680
WIRE -320 224 -320 96
WIRE -320 432 -320 304
WIRE -320 464 -320 432
WIRE -320 544 -320 528
WIRE -224 96 -320 96
WIRE -224 128 -224 96
WIRE -224 240 -224 208
WIRE -224 272 -224 240
WIRE -224 432 -320 432
WIRE -224 432 -224 368
WIRE -160 448 -160 320
WIRE -144 96 -224 96
WIRE -96 240 -224 240
WIRE -96 272 -96 240
WIRE -96 432 -224 432
WIRE -96 432 -96 368
WIRE -32 240 -96 240
WIRE 16 96 -64 96
WIRE 16 160 16 96
WIRE 16 320 -32 320
WIRE 16 320 16 256
WIRE 16 336 16 320
WIRE 16 432 -96 432
WIRE 16 432 16 416
WIRE 48 448 -160 448
WIRE 48 448 48 208
WIRE 48 464 48 448
WIRE 64 96 16 96
WIRE 64 208 48 208
WIRE 160 96 128 96
WIRE 160 208 144 208
WIRE 160 208 160 96
WIRE 160 352 160 208
WIRE 160 544 160 416
WIRE 240 96 160 96
WIRE 256 96 240 96
WIRE 256 272 256 96
WIRE 256 544 256 352
FLAG 240 96 out
FLAG 48 544 0
FLAG -320 544 0
FLAG 160 544 0
FLAG 256 544 0
SYMBOL nmos -32 160 R0
WINDOW 0 31 -9 Right 0
WINDOW 3 -33 105 Left 0
SYMATTR InstName M1
SYMATTR Value IRF740
SYMBOL ind -160 112 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L1
SYMATTR Value 330µ
SYMBOL cap 176 352 M0
SYMATTR InstName C1
SYMATTR Value 1µ
SYMATTR SpiceLine Rser=100m
SYMBOL diode 64 80 M90
WINDOW 0 39 30 VTop 0
WINDOW 3 -7 56 VBottom 0
SYMATTR InstName D1
SYMATTR Value UPSC600
SYMBOL Misc\\battery -320 208 M0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value {Ub}
SYMBOL Misc\\EuropeanResistor 32 320 M0
WINDOW 0 16 71 VLeft 0
SYMATTR InstName R1
SYMATTR Value .47
SYMBOL Misc\\EuropeanResistor 64 448 M0
WINDOW 0 15 68 VLeft 0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL Misc\\EuropeanResistor 48 192 M90
WINDOW 0 30 55 VBottom 0
WINDOW 3 27 56 VTop 0
SYMATTR InstName R3
SYMATTR Value 150k
SYMBOL Misc\\EuropeanResistor -240 112 R0
WINDOW 0 17 41 VRight 0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL Misc\\EuropeanResistor 272 256 M0
WINDOW 3 12 -224 Left 0
SYMATTR Value R=if(time < 2m,1G,if(time < 4m, 20k, 5k))
SYMATTR InstName Rload
SYMBOL npn -32 272 M0
WINDOW 0 47 27 Left 0
WINDOW 3 25 52 Left 0
SYMATTR InstName Q2
SYMATTR Value BC547C
SYMBOL npn -160 272 M0
WINDOW 0 47 27 Left 0
WINDOW 3 25 52 Left 0
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL zener -336 464 R0
WINDOW 3 56 35 Left 0
SYMATTR InstName D2
SYMATTR Value BZX84C3V9L
TEXT -162 -48 Left 0 !.tran 0 6m 0 uic
TEXT -160 -112 Left 0 !;.step param Ub list 60 48 24 12\n.param Ub 12