Version 4
SHEET 1 1324 776
WIRE 224 -64 16 -64
WIRE 432 -64 224 -64
WIRE 16 16 16 -64
WIRE 224 16 224 -64
WIRE 432 16 432 -64
WIRE 16 160 16 96
WIRE 80 160 16 160
WIRE 224 160 224 96
WIRE 224 160 160 160
WIRE 288 160 224 160
WIRE 432 160 432 96
WIRE 432 160 368 160
WIRE 224 192 224 160
FLAG 224 192 0
SYMBOL voltage 64 160 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 -32 56 VBottom 2
WINDOW 123 -60 56 VBottom 2
WINDOW 39 0 0 Left 2
SYMATTR InstName Va
SYMATTR Value 10
SYMBOL voltage 272 160 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 -32 56 VBottom 2
WINDOW 123 -60 56 VBottom 2
WINDOW 39 0 0 Left 2
SYMATTR InstName Vb
SYMATTR Value 20
SYMBOL Misc\\EuropeanResistor 208 0 R0
SYMATTR InstName R2
SYMATTR Value {R2}
SYMBOL Misc\\EuropeanResistor 0 112 M180
WINDOW 0 31 76 Left 2
WINDOW 3 31 40 Left 2
SYMATTR InstName R1
SYMATTR Value {R1}
SYMBOL Misc\\EuropeanResistor 416 0 R0
SYMATTR InstName R3
SYMATTR Value {R3}
TEXT 8 -240 Left 2 !.op
TEXT 56 -24 Left 2 ;I1
TEXT 456 -24 Left 2 ;I2
TEXT 248 -24 Left 2 ;I1-I2
TEXT -8 312 Left 2 ;Einschränkungen für die Wahl von R2\n \nI1*(R1+R2) -I2*R2 -Ua = 0 (1)\n \n-I1*R2  +I2*(R2+R3) -Ub = 0 (2)\n \nAus (1)\n \nR1 = (Ua -(I1-I2)*R2)/I1\n \nBedingung:  R2 < Ua/(I1-I2)\n \nAus (2)\n \nR3 = (Ub -(I2-I1)*R2)/I2\n \nBedingung: R2 < Ub/(I2-I1)
TEXT 0 -280 Left 2 !.step param R2 list 1m 1 2 3 4 5 6 7 8 9 10 12 14 16 18 20 25 30 35 39.999
TEXT 0 -496 Left 2 !.param I1=1\n.param I2=1.5\n.param R2=10\n.param Ua=10\n.param Ub=20
TEXT 0 -344 Left 2 !.param R1 = (Ua -(I1-I2)*R2)/I1\n.param R3 = (Ub -(I2-I1)*R2)/I2
TEXT 8 -152 Left 2 !.meas R1_ PARAM R1\n.meas R3_ PARAM R3
TEXT 8 -208 Left 2 !.tran 1m
LINE Normal 0 -16 16 -32 2
LINE Normal 32 -16 16 -32 2
LINE Normal 416 -32 432 -16 2
LINE Normal 448 -32 432 -16 2
LINE Normal 208 -32 224 -16 2
LINE Normal 240 -32 224 -16 2