SCR, short for thyristor rectifier, is a four-layer high-power semiconductor device with three PN junctions, also known as a thyristor. It has the characteristics of small size, relatively simple structure and strong function, and is one of the more commonly used semiconductor devices. The device is widely used in various electronic equipment and electronic products, and is used for controllable rectification, inverter, frequency conversion, voltage regulation, and non-contact switching. upper case aluminum,keyboard frame,keyboard case hot swappable,customizable keyboard case Dongguan Yingxin Technology Co., Ltd. , https://www.yingxinelectronic.com