* SPICE netlist
D1 N001 N008 1N914
D2 N008 N010 1N914
R2 N010 0 4.98K
R1 0 N001 907
Q3 0 N002 N004 0 2N2222
Q2 0 N001 N003 0 2N2222
QA N002 N006 N009 0 2N2222
QB N002 N005 N009 0 2N2222
QR N001 N007 N009 0 2N2222
Q1 0 N001 N007 0 2N2222
RE N009 -5.2 777
RB N005 0 5OK
RA N006 0 5OK
RC1 0 N002 217
RC2 0 N001 245
RT2 N004 -2 50
RT1 N003 -2 50
R3 N007 0 6.1K
V1 N006 0 5
V2 N005 0 5
.tran 3m

* LTspice schematic (.asc)
Version 4
SHEET 1 1248 704
WIRE -64 -272 -64 -352
WIRE -64 -272 -336 -272
WIRE 80 -272 -64 -272
WIRE 192 -272 80 -272
WIRE 448 -272 448 -336
WIRE 448 -272 352 -272
WIRE 528 -272 448 -272
WIRE -64 -256 -64 -272
WIRE 192 -240 192 -272
WIRE -336 -208 -336 -272
WIRE 528 -208 528 -272
WIRE -64 -160 -64 -176
WIRE 192 -160 -64 -160
WIRE 464 -160 192 -160
WIRE 352 -144 352 -272
WIRE -336 -96 -336 -128
WIRE 288 -96 -336 -96
WIRE 80 -80 80 -272
WIRE 528 -80 528 -112
WIRE 624 -80 528 -80
WIRE 192 -32 192 -160
WIRE 192 -32 144 -32
WIRE -336 0 -336 -96
WIRE -336 0 -480 0
WIRE -256 0 -336 0
WIRE 192 16 192 -32
WIRE -480 32 -480 0
WIRE -256 32 -256 0
WIRE -64 32 -64 -160
WIRE 352 32 352 -48
WIRE 480 32 352 32
WIRE 624 32 624 -80
WIRE -384 64 -432 64
WIRE -576 80 -624 80
WIRE -544 80 -576 80
WIRE -384 80 -384 64
WIRE -352 80 -384 80
WIRE -320 80 -352 80
WIRE 32 80 0 80
WIRE 80 80 80 16
WIRE 80 80 32 80
WIRE 32 128 32 80
WIRE 192 128 192 80
WIRE 480 128 480 32
WIRE -576 144 -576 80
WIRE -480 160 -480 128
WIRE -256 160 -256 128
WIRE -256 160 -480 160
WIRE -160 160 -256 160
WIRE -64 160 -64 128
WIRE -64 160 -160 160
WIRE -624 192 -624 160
WIRE -432 192 -432 144
WIRE -352 192 -352 80
WIRE -160 208 -160 160
WIRE 624 208 624 112
WIRE 192 224 192 192
WIRE -576 256 -576 224
WIRE 32 272 32 208
WIRE -352 304 -352 272
WIRE 480 304 480 208
WIRE -160 320 -160 288
WIRE 192 352 192 304
FLAG 192 352 0
FLAG 480 304 -2
FLAG 624 208 -2
FLAG 32 272 0
FLAG -160 320 -5.2
FLAG -352 304 0
FLAG -576 256 0
FLAG -64 -352 0
FLAG 448 -336 0
FLAG -624 192 0
FLAG -432 192 0
SYMBOL diode 176 16 R0
SYMATTR InstName D1
SYMATTR Value 1N914
SYMBOL diode 176 128 R0
SYMATTR InstName D2
SYMATTR Value 1N914
SYMBOL res 176 208 R0
SYMATTR InstName R2
SYMATTR Value 4.98K
SYMBOL res 176 -256 R0
SYMATTR InstName R1
SYMATTR Value 907
SYMBOL npn 288 -144 R0
SYMATTR Value 2N2222
SYMATTR InstName Q3
SYMBOL npn 464 -208 R0
SYMATTR InstName Q2
SYMATTR Value 2N2222
SYMBOL npn -544 32 R0
SYMATTR InstName QA
SYMATTR Value 2N2222
SYMBOL npn -320 32 R0
SYMATTR InstName QB
SYMATTR Value 2N2222
SYMBOL npn 0 32 M0
SYMATTR InstName QR
SYMATTR Value 2N2222
SYMBOL npn 144 -80 M0
SYMATTR InstName Q1
SYMATTR Value 2N2222
SYMBOL res -176 192 R0
SYMATTR InstName RE
SYMATTR Value 777
SYMBOL res -368 176 R0
SYMATTR InstName RB
SYMATTR Value 5OK
SYMBOL res -592 128 R0
SYMATTR InstName RA
SYMATTR Value 5OK
SYMBOL res -352 -224 R0
SYMATTR InstName RC1
SYMATTR Value 217
SYMBOL res -80 -272 R0
SYMATTR InstName RC2
SYMATTR Value 245
SYMBOL res 464 112 R0
SYMATTR InstName RT2
SYMATTR Value 50
SYMBOL res 608 16 R0
SYMATTR InstName RT1
SYMATTR Value 50
SYMBOL res 16 112 R0
SYMATTR InstName R3
SYMATTR Value 6.1K
SYMBOL voltage -624 64 R0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL voltage -432 48 R0
SYMATTR InstName V2
SYMATTR Value 5
ARC Normal -368 384 -364 388 -368 388 -368 384 2