Version 4
SHEET 1 880 680
WIRE 80 -96 -176 -96
WIRE 256 -96 80 -96
WIRE 432 -96 256 -96
WIRE 256 -64 256 -96
WIRE 432 16 432 -96
WIRE -176 32 -176 -96
WIRE 256 64 256 16
WIRE 304 64 256 64
WIRE 368 64 304 64
WIRE 80 144 80 -96
WIRE 256 144 256 64
WIRE -176 160 -176 112
WIRE -176 160 -224 160
WIRE -224 176 -224 160
WIRE -16 192 -64 192
WIRE 16 192 -16 192
WIRE 352 192 320 192
WIRE 368 192 352 192
WIRE 432 192 432 112
WIRE 480 192 432 192
WIRE 496 192 480 192
WIRE -176 208 -176 160
WIRE 368 224 368 192
WIRE -64 240 -64 192
WIRE 160 240 80 240
WIRE 256 240 160 240
WIRE 160 320 160 240
WIRE 432 320 432 192
WIRE -176 400 -176 288
WIRE 160 400 -176 400
WIRE 432 400 160 400
FLAG 480 192 out2
FLAG 304 64 out1
FLAG -64 240 0
FLAG 368 304 0
FLAG 160 240 tail
FLAG -16 192 left
FLAG 352 192 right
FLAG -224 176 0
SYMBOL npn 16 144 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL npn 320 144 M0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL pnp 368 112 M180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL res 144 304 R0
SYMATTR InstName Rtail
SYMATTR Value 10k
SYMBOL res 240 -80 R0
SYMATTR InstName R2
SYMATTR Value 20k
SYMBOL res 416 304 R0
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL voltage -176 16 R0
SYMATTR InstName V1
SYMATTR Value 6
SYMBOL voltage -176 192 R0
SYMATTR InstName V2
SYMATTR Value 6
SYMBOL voltage 368 208 R0
SYMATTR InstName V4
SYMATTR Value 0
TEXT -232 408 Left 2 !.dc v4 -6 6 0.001