surface varactor

例句：

1. 1.The device is used to control the brightness of LED lights on a computer screen.
   这种设备用于控制计算机屏幕上LED灯的亮度。
2. 2.The surface varactor plays an important role in maintaining the stability of the circuit.
   表面变容器在保持电路稳定性方面起着重要作用。
3. 3.The surface varactor is a crucial component in the electronic circuitry of modern smartphones.
   表面变容器是现代智能手机电子电路中至关重要的组件。