Version 4
SHEET 1 1324 680
WIRE 528 -160 192 -160
WIRE 960 -160 528 -160
WIRE 1264 -160 960 -160
WIRE 960 -32 960 -160
WIRE 528 -16 528 -160
WIRE 192 32 192 -160
WIRE 528 96 528 64
WIRE 640 96 528 96
WIRE 960 96 960 48
WIRE 1024 96 960 96
WIRE 1264 112 1264 -160
WIRE 528 128 528 96
WIRE 960 160 960 96
WIRE -144 176 -144 112
WIRE 32 176 -144 176
WIRE 192 176 192 112
WIRE 192 176 112 176
WIRE 304 176 192 176
WIRE 464 176 384 176
WIRE 640 208 640 96
WIRE 720 208 640 208
WIRE 864 208 800 208
WIRE 896 208 864 208
WIRE 192 240 192 176
WIRE -144 288 -144 176
WIRE 528 320 528 224
WIRE 960 320 960 256
WIRE 960 320 528 320
WIRE 864 336 864 208
WIRE 528 368 528 320
WIRE -144 496 -144 368
WIRE 192 496 192 320
WIRE 192 496 -144 496
WIRE 528 496 528 448
WIRE 528 496 192 496
WIRE 864 496 864 416
WIRE 864 496 528 496
WIRE 1264 496 1264 192
WIRE 1264 496 864 496
WIRE 192 544 192 496
FLAG 192 544 0
FLAG 1024 96 Out
FLAG -144 112 In
SYMBOL res 128 160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 25k
SYMBOL res 208 128 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R2
SYMATTR Value 7.5k
SYMBOL res 208 336 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R3
SYMATTR Value 25k
SYMBOL npn 464 128 R0
SYMATTR InstName Q1
SYMATTR Value BC847C
SYMBOL res 400 160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 100k
SYMBOL res 512 -32 R0
SYMATTR InstName R5
SYMATTR Value 1k
SYMBOL voltage 1264 96 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 3
SYMBOL voltage -144 272 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value SINE(0 10 50 0 0 270)
SYMBOL res 944 -48 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL npn 896 160 R0
SYMATTR InstName Q2
SYMATTR Value BC847C
SYMBOL res 816 192 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 500
SYMBOL res 880 432 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R8
SYMATTR Value 1k
SYMBOL res 544 464 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R9
SYMATTR Value 100
TEXT -136 536 Left 2 !.tran 20m