Verified answer

Bonsoir,

Conductance = 1/R  

Résistance équivalente à R2 , R3 , R4 et R5  

= 1/Re = 1/R2 + 1/R3 + 1/(R4+R5)

            = 1/2000 + 1/2000 + 1/1000

            = 4/2000 = 0.002  

Re = 1/0.002 = 500 ohms

Rt = R1 + Re = 1500 ohms = 1.5 Kohms

Intensité fournie par E =  Tension / Résistance totale = 15 / 1500 = 0.01 = 10 mA

I1 = It = 10 mA

I2 = U2/R2 = 2.5 mA

I3 = U3/R3 = 2.5 mA

I4.5 = It - (I2 + I3) =  5 mA

U2 = 5 Volts

U3 = Ue - U1 = 15 - (0.01 * 1000) = 15 - 10 = 5 Volts

U4 + U5 = 5 Volts

U4 = R4 * I4.5 = 750 * 0.005 = 3.75 Volts

U5 = 5 - U4 = 5 - 3.75 = 1.25 Volts