Version 4
SHEET 1 880 680
WIRE 96 -16 32 -16
WIRE 240 -16 96 -16
WIRE 96 0 96 -16
WIRE 240 96 240 64
WIRE 96 144 96 64
WIRE 176 144 96 144
WIRE 240 208 240 192
WIRE 288 208 240 208
WIRE 96 240 96 144
WIRE 240 240 240 208
WIRE 96 336 96 320
WIRE 96 336 32 336
WIRE 240 336 240 304
WIRE 240 336 96 336
FLAG 32 336 0
FLAG 32 -16 Ub
FLAG 288 208 Ref
SYMBOL res 80 224 R0
SYMATTR InstName R1
SYMATTR Value 470K
SYMATTR SpiceLine tol=1
SYMBOL res 224 -32 R0
SYMATTR InstName R2
SYMATTR Value 150K
SYMBOL LED 80 0 R0
SYMATTR InstName D1
SYMBOL pnp 176 192 M180
SYMATTR InstName Q1
SYMBOL zener 256 304 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D2