✔ 最佳答案
Refer to the figure below.
V(AC) = V(BD) = V(BE) = 20V
The equivalent resistance of R₄ and R₅, R₄₅
= 1 / [(1/8) + (1/8)] kΩ
= 4 kΩ
The equivalent resistance of R₃, R₄ and R₅, R₃₄₅
= (4 + 6) kΩ
= 10 kΩ
The equivalent resistance of the whole circuit, Rₛ
= 1 / [(1/25) + (1/10) + (1/10)] kΩ
= 4.167 kΩ
V(AC) = Iₛ Rₛ
20 V = Iₛ (4.167 kΩ)
Iₛ = 4.800 mA
====
b)
V(BE) = I₁ R₃₄₅
20 V = I₁ (10 kΩ)
I₁ = 2 mA
V₁ = I₁ R₄₅
V₁ = (2mA) × (4 kΩ)
V₁ = 8.000 V
OR:
V₁ = Vₛ × (R₄₅/R₃₄₅)
V₁ = (20 V) × (4/10)
V₁ = 8.000 V