Version 4
SHEET 1 880 680
WIRE 64 16 48 16
WIRE 192 16 144 16
WIRE 272 16 192 16
WIRE 272 96 272 16
WIRE 48 112 48 16
WIRE 192 144 192 16
WIRE 208 144 192 144
WIRE 48 272 48 192
WIRE 272 272 272 208
WIRE 272 272 48 272
WIRE 48 288 48 272
FLAG 48 288 0
SYMBOL Misc\\battery 48 96 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 3
SYMBOL res 160 0 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL Misc\\TL431TI 272 160 R0
SYMATTR InstName U1
TEXT 16 312 Left 2 !.tran 10m