vacuum tube emission

例句：

1. 1.The vacuum tube was used in the early electronics industry.
   真空管在早期的电子工业中被使用。
2. 2.The vacuum tube is a type of electronic device that produces high-frequency signals.
   真空管是一种产生高频信号的电子设备。
3. 3. The vacuum tube was replaced by transistors in the 1950s, but it remains popular among hobbyists and collectors.
   真空管在20世纪50年代被晶体管取代，但仍然受到业余爱好者和收藏家的欢迎。