1 如圖所示之電路,開關 S 在t = 0秒時閉合,若電感器的初始能量為零,則電路時間常數 τ 與 t = 1秒 時之電感器電流 𝑖L分別為何? 104 統測
A τ = 1ms, 𝑖L = 2.4A
B τ = 1ms, 𝑖L = 1.2A
C τ = 2ms, 𝑖L = 2.4A
D τ = 2ms, 𝑖L = 1.2A

化戴維寧等效電阻
Rth = 6//6+2 = 5Ω
Eth = 12×66+6 = 6V
τ = 5m/5 = 1ms
t = 1秒 已經 穩態, 𝑖L = 6/5 = 1.2A