5. 如下圖所示電路, = 15V, = 2MΩ, = 1MΩ, = 2V, K = 0.25mA / V 2 , = 10kΩ , = 1kΩ ,若將電路接成一共源極放大器,試求:
(3)若考慮= 20kΩ ,則 為何?