Version 4
SHEET 1 2660 680
WIRE 960 -336 624 -336
WIRE 624 -240 624 -336
WIRE 960 -240 960 -336
WIRE 1200 -160 960 -160
WIRE 1440 -80 960 -80
WIRE 1664 0 960 0
WIRE 1904 80 960 80
WIRE 96 96 96 80
WIRE 96 96 -32 96
WIRE -32 112 -32 96
WIRE 96 128 96 96
WIRE 2144 160 960 160
WIRE 2384 240 960 240
FLAG -32 112 0
FLAG 96 208 Vee
FLAG 96 0 Vcc
FLAG 1344 -352 Vcc
FLAG 1344 -112 0
FLAG 624 -160 0
FLAG 960 400 0
FLAG 1584 -272 Vcc
FLAG 1584 -32 0
FLAG 1808 -192 Vcc
FLAG 1808 48 0
FLAG 2048 -112 Vcc
FLAG 2048 128 0
FLAG 2288 -32 Vcc
FLAG 2288 208 0
FLAG 2528 48 Vcc
FLAG 2528 288 0
SYMBOL voltage 96 -16 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL voltage 96 112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL npn 1280 -208 R0
SYMATTR InstName Q1
SYMATTR Value BC547B
SYMBOL LED 1328 -272 R0
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1328 -368 R0
SYMATTR InstName R1
SYMATTR Value {Rdiode}
SYMBOL res 944 -256 R0
SYMATTR InstName R2
SYMATTR Value 560
SYMBOL res 944 -176 R0
SYMATTR InstName R3
SYMATTR Value {Rladder}
SYMBOL res 944 -96 R0
SYMATTR InstName R4
SYMATTR Value {Rladder}
SYMBOL res 944 -16 R0
SYMATTR InstName R5
SYMATTR Value {Rladder}
SYMBOL res 944 64 R0
SYMATTR InstName R6
SYMATTR Value {Rladder}
SYMBOL res 944 144 R0
SYMATTR InstName R7
SYMATTR Value {Rladder}
SYMBOL res 944 224 R0
SYMATTR InstName R8
SYMATTR Value {Rladder}
SYMBOL voltage 624 -256 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 10 0 1 1 0)
SYMBOL res 1184 -144 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R9
SYMATTR Value {Rbase}
SYMBOL npn 1520 -128 R0
SYMATTR InstName Q2
SYMATTR Value BC547B
SYMBOL LED 1568 -192 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1568 -288 R0
SYMATTR InstName R10
SYMATTR Value {Rdiode}
SYMBOL res 1424 -64 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R11
SYMATTR Value {Rbase}
SYMBOL npn 1744 -48 R0
SYMATTR InstName Q3
SYMATTR Value BC547B
SYMBOL LED 1792 -112 R0
SYMATTR InstName D3
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1792 -208 R0
SYMATTR InstName R12
SYMATTR Value {Rdiode}
SYMBOL res 1648 16 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R13
SYMATTR Value {Rbase}
SYMBOL npn 1984 32 R0
SYMATTR InstName Q4
SYMATTR Value BC547B
SYMBOL LED 2032 -32 R0
SYMATTR InstName D4
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 2032 -128 R0
SYMATTR InstName R14
SYMATTR Value {Rdiode}
SYMBOL res 1888 96 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R15
SYMATTR Value {Rbase}
SYMBOL npn 2224 112 R0
SYMATTR InstName Q5
SYMATTR Value BC547B
SYMBOL LED 2272 48 R0
SYMATTR InstName D5
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 2272 -48 R0
SYMATTR InstName R16
SYMATTR Value {Rdiode}
SYMBOL res 2128 176 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R17
SYMATTR Value {Rbase}
SYMBOL npn 2464 192 R0
SYMATTR InstName Q6
SYMATTR Value BC547B
SYMBOL LED 2512 128 R0
SYMATTR InstName D6
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 2512 32 R0
SYMATTR InstName R18
SYMATTR Value {Rdiode}
SYMBOL res 2368 256 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R19
SYMATTR Value {Rbase}
SYMBOL voltage 960 304 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V4
SYMATTR Value -.6
TEXT 88 -376 Left 2 !.param Rladder=100
TEXT 88 -328 Left 2 !.param Rdiode=100
TEXT -52 330 Left 2 !.tran 1
TEXT 88 -280 Left 2 !.param Rbase=10k