Version 4
SHEET 1 880 692
WIRE -352 -304 -352 -352
WIRE -368 112 -368 96
WIRE 160 144 160 96
WIRE -208 160 -208 96
WIRE 0 192 0 176
WIRE 96 192 0 192
WIRE 592 192 592 144
WIRE -368 208 -368 192
WIRE -272 208 -368 208
WIRE 528 240 448 240
WIRE 160 256 160 240
WIRE 592 288 512 288
WIRE 448 384 448 336
WIRE 592 384 592 288
WIRE -208 432 -208 256
WIRE -368 480 -368 464
WIRE -272 480 -368 480
WIRE -208 544 -208 528
FLAG 0 384 0
FLAG 160 336 0
FLAG -352 -224 0
FLAG -368 672 0
FLAG -208 624 0
FLAG -352 -352 +
IOPIN -352 -352 BiDir
FLAG -208 96 +
IOPIN -208 96 BiDir
FLAG 160 96 +
IOPIN 160 96 BiDir
FLAG 448 384 0
FLAG 592 464 0
FLAG -80 -208 0
FLAG 592 144 +
IOPIN 592 144 BiDir
FLAG -80 -288 20
IOPIN -80 -288 BiDir
FLAG -368 96 20
IOPIN -368 96 BiDir
FLAG 0 96 20
IOPIN 0 96 BiDir
FLAG 448 160 20
IOPIN 448 160 BiDir
SYMBOL npn 96 144 R0
SYMATTR InstName Q1
SYMATTR Value PH_BC547B
SYMBOL diode -16 192 R0
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL diode -16 256 R0
SYMATTR InstName D2
SYMATTR Value 1N4148
SYMBOL diode -16 320 R0
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL Misc\\EuropeanResistor 144 240 R0
SYMATTR InstName R1
SYMATTR Value 470
SYMBOL voltage -352 -320 R0
WINDOW 123 24 124 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(20 1m 20k)
SYMATTR Value2 AC 1
SYMBOL Misc\\EuropeanResistor -16 80 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL npn -272 432 R0
SYMATTR InstName Q2
SYMATTR Value PH_BC547B
SYMBOL diode -384 480 R0
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL diode -384 544 R0
SYMATTR InstName D5
SYMATTR Value 1N4148
SYMBOL diode -384 608 R0
SYMATTR InstName D6
SYMATTR Value 1N4148
SYMBOL Misc\\EuropeanResistor -224 528 R0
SYMATTR InstName R3
SYMATTR Value 470
SYMBOL diode -384 400 R0
SYMATTR InstName D7
SYMATTR Value 1N4148
SYMBOL diode -384 336 R0
SYMATTR InstName D8
SYMATTR Value 1N4148
SYMBOL diode -384 272 R0
SYMATTR InstName D9
SYMATTR Value 1N4148
SYMBOL diode -384 208 R0
SYMATTR InstName D10
SYMATTR Value 1N4148
SYMBOL npn -272 160 R0
SYMATTR InstName Q3
SYMATTR Value PH_BC547B
SYMBOL Misc\\EuropeanResistor -384 96 R0
SYMATTR InstName R4
SYMATTR Value 8k
SYMBOL Misc\\EuropeanResistor 576 480 M180
WINDOW 0 31 76 Left 2
WINDOW 3 31 40 Left 2
SYMATTR InstName R5
SYMATTR Value 240
SYMBOL npn 528 192 R0
WINDOW 0 61 67 Left 2
WINDOW 3 51 32 Left 2
SYMATTR InstName Q4
SYMATTR Value PH_BC547B
SYMBOL npn 512 240 M0
WINDOW 0 61 67 Left 2
WINDOW 3 51 32 Left 2
SYMATTR InstName Q5
SYMATTR Value PH_BC547B
SYMBOL Misc\\EuropeanResistor 432 144 R0
SYMATTR InstName R6
SYMATTR Value 73k
SYMBOL voltage -80 -304 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 20
TEXT 312 -128 Left 2 !;tran 0 0.3m 0 20n
TEXT -32 -128 Left 2 !.OPTIONS plotwinsize=0
TEXT -24 -64 Left 2 !.OPTIONS numdgt=9
TEXT 280 -56 Left 2 !.ac dec 1000 10 10meg