Version 4
SHEET 1 880 680
WIRE 432 -32 64 -32
WIRE -192 -16 -192 -96
WIRE -48 -16 -48 -96
WIRE 208 32 128 32
WIRE 336 32 208 32
WIRE 208 48 208 32
WIRE 336 96 336 32
WIRE -192 128 -192 64
WIRE -48 128 -48 64
WIRE 272 144 240 144
WIRE 128 224 128 32
WIRE 64 240 64 -32
WIRE 96 240 64 240
WIRE 240 256 240 144
WIRE 240 256 160 256
WIRE 272 256 240 256
WIRE 336 256 336 192
WIRE 432 256 432 -32
WIRE 432 256 336 256
WIRE 592 256 592 240
WIRE 592 256 432 256
WIRE -48 272 -48 256
WIRE -48 272 -192 272
WIRE 96 272 -48 272
WIRE 336 304 336 256
WIRE -192 320 -192 272
WIRE 592 320 592 256
WIRE 240 352 240 256
WIRE 272 352 240 352
WIRE 592 432 592 400
WIRE -192 448 -192 400
WIRE 128 464 128 288
WIRE 208 464 208 448
WIRE 208 464 128 464
WIRE 336 464 336 400
WIRE 336 464 208 464
FLAG -48 128 0
FLAG -192 128 0
FLAG 592 432 0
FLAG -192 -96 +UB
FLAG 208 48 +UB
FLAG -48 -96 -UB
FLAG 208 448 -UB
FLAG -192 448 0
FLAG -48 256 Ue
FLAG 592 240 Ua
FLAG 272 256 Ux
SYMBOL Opamps\\UniversalOpamp2 128 256 R0
SYMATTR InstName U1
SYMBOL pnp 272 400 M180
SYMATTR InstName Q1
SYMBOL npn 272 96 R0
SYMATTR InstName Q2
SYMBOL voltage -192 -32 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL voltage -48 80 R180
WINDOW 0 24 96 Left 2
WINDOW 3 24 16 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL res 576 304 R0
SYMATTR InstName R1
SYMATTR Value 20
SYMBOL voltage -192 304 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V3
SYMATTR Value PULSE(0 12 0 1 1 0)
TEXT -226 496 Left 2 !.tran 2