Ucea = 5
Ica = 0.008
Rk = Ucea/Ica = 5/0.008 = 625
Uea = 0.3Ucea = 1.5
Re = 0.3Ucea/Ica = 187.5
E1 = 2.3Ucea = 11.5
Ueba = 0.145
Iba = 0.18
System:
I1R1+I2R2 = E1
I1+Iba = I2
I2R2 = Ueba + Uea
Rb = (R1R2/(R1+R2)) = 5
Как-то так.