Version 4
SHEET 1 1300 680
WIRE -128 -256 -160 -256
WIRE -64 -256 -128 -256
WIRE 368 -256 160 -256
WIRE 528 -256 368 -256
WIRE 928 -256 528 -256
WIRE -160 -224 -160 -256
WIRE 160 -208 160 -256
WIRE 368 -208 368 -256
WIRE 928 -208 928 -256
WIRE 272 -160 224 -160
WIRE 304 -160 272 -160
WIRE -64 -128 -64 -256
WIRE -160 -112 -160 -144
WIRE -160 -112 -224 -112
WIRE -224 -96 -224 -112
WIRE -160 -80 -160 -112
WIRE 272 -80 272 -160
WIRE 320 -80 272 -80
WIRE 368 -80 368 -112
WIRE 368 -80 320 -80
WIRE 160 -64 160 -112
WIRE 928 -48 928 -128
WIRE 160 0 160 -64
WIRE 736 0 160 0
WIRE 864 0 736 0
WIRE -160 64 -160 0
WIRE -128 64 -160 64
WIRE -64 64 -64 -64
WIRE -64 64 -128 64
WIRE 736 112 736 0
WIRE 784 112 736 112
WIRE 928 112 928 48
WIRE 928 112 848 112
WIRE 160 144 160 0
WIRE 368 144 368 -80
WIRE 64 192 -160 192
WIRE 96 192 64 192
WIRE 464 192 432 192
WIRE 480 192 464 192
WIRE 480 256 480 192
WIRE -160 288 -160 192
WIRE 160 288 160 240
WIRE 256 288 160 288
WIRE 368 288 368 240
WIRE 368 288 256 288
WIRE 928 288 928 112
WIRE 1104 288 928 288
WIRE 1136 288 1104 288
WIRE 928 320 928 288
WIRE 256 368 256 288
WIRE -160 432 -160 368
WIRE 256 544 256 448
WIRE 496 544 256 544
WIRE 928 544 928 400
WIRE 928 544 496 544
FLAG -224 -96 0
FLAG -128 -256 Vcc
FLAG -128 64 Vee
FLAG 496 544 Vee
FLAG 1104 288 out
FLAG -160 432 0
FLAG 64 192 a
FLAG 464 192 b
FLAG 528 -256 Vcc
FLAG 480 256 0
FLAG 160 -64 x
FLAG 320 -80 y
SYMBOL npn 96 144 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL npn 432 144 M0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL res 240 352 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL voltage -160 -240 R0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL voltage -160 -96 R0
SYMATTR InstName V2
SYMATTR Value 5
SYMBOL pnp 864 48 M180
SYMATTR InstName Q6
SYMATTR Value 2N3906
SYMBOL res 912 304 R0
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL res 912 -224 R0
SYMATTR InstName R6
SYMATTR Value 10
SYMBOL Misc\\signal -160 272 R0
WINDOW 123 24 132 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value2 AC 1
SYMATTR InstName Vin
SYMBOL cap 848 96 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName Cc
SYMATTR Value 220p
SYMBOL pnp 304 -112 M180
SYMATTR InstName Q4
SYMATTR Value 2N3906
SYMBOL pnp 224 -112 R180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL cap -80 -128 R0
SYMATTR InstName C2
SYMATTR Value 10u
TEXT -248 592 Left 2 !.dc Vin -600m 600m 1u
TEXT 72 584 Left 2 !.meas DC find v(a) when v(out)=0