thermionic vacuum tube

例句：

1. 1.Thermionic vacuum tubes are used in electronic devices to amplify signals.
   热电子管在电子设备中用于放大信号。
2. 2.Thermionic valves are commonly used in air conditioners and heating systems.
   热电子阀常用于空调和取暖系统。
3. 3.Thermionic valves have been replaced by transistors due to their lower power consumption.
   由于功率消耗较低，热电子阀已被晶体管所取代。