Version 4
SHEET 1 1020 680
WIRE 80 0 -480 0
WIRE 960 0 80 0
WIRE 80 32 80 0
WIRE -592 64 -656 64
WIRE -480 128 -480 0
WIRE 80 128 80 112
WIRE 688 128 80 128
WIRE -592 144 -592 64
WIRE -528 144 -592 144
WIRE 80 160 80 128
WIRE 688 160 688 128
WIRE -560 192 -688 192
WIRE -528 192 -560 192
WIRE 960 192 960 0
WIRE -688 240 -688 192
WIRE 688 304 688 224
WIRE -480 320 -480 208
WIRE -288 320 -480 320
WIRE 80 320 80 224
WIRE 80 320 -288 320
WIRE -288 352 -288 320
WIRE 80 352 80 320
WIRE 128 352 80 352
WIRE 224 352 208 352
WIRE 352 352 288 352
WIRE 464 352 416 352
WIRE 592 352 528 352
WIRE 624 352 592 352
WIRE -336 368 -368 368
WIRE -560 416 -560 192
WIRE -336 416 -560 416
WIRE 592 432 592 352
WIRE 688 432 688 400
WIRE 688 432 672 432
WIRE 688 448 688 432
WIRE 960 448 960 272
WIRE 960 448 688 448
WIRE -688 464 -688 320
WIRE -288 464 -288 432
WIRE 688 464 688 448
FLAG 688 464 0
FLAG -688 464 0
FLAG -736 64 0
FLAG -288 464 0
FLAG -448 368 0
SYMBOL res 64 16 R0
SYMATTR InstName R1
SYMATTR Value 4k7
SYMBOL LED 64 160 R0
SYMATTR InstName D1
SYMATTR Value NSPW500BS
SYMBOL LED 672 160 R0
SYMATTR InstName D2
SYMATTR Value NSPW500BS
SYMBOL npn 624 304 R0
SYMATTR InstName Q1
SYMATTR Value BC847C
SYMBOL res 224 336 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 15k
SYMBOL voltage 960 176 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL sw -480 112 R0
SYMATTR InstName S1
SYMBOL voltage -688 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value SINE(0 3 100)
SYMBOL voltage -640 64 R90
WINDOW 0 -32 56 VBottom 0
WINDOW 3 32 56 VTop 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value 2
SYMBOL sw -288 448 M180
SYMATTR InstName S2
SYMBOL voltage -352 368 R90
WINDOW 0 -32 56 VBottom 0
WINDOW 3 32 56 VTop 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V4
SYMATTR Value -2
SYMBOL diode 224 368 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL diode 352 368 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL diode 464 368 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName D5
SYMATTR Value 1N4148
SYMBOL res 688 416 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R3
SYMATTR Value 6k8
TEXT -18 488 Left 0 !.tran 100m
TEXT -480 -80 Left 0 !.model SW SW(Ron=1 Roff=10Meg Vt=.5 Vh=-.4)