七极真空管

例句：

1. 1. This type of vacuum tube is commonly used in electronic devices.
   这种真空管在电子设备中常用。
2. 2. The engineer was able to repair the seven-pole vacuum tube successfully.
   工程师成功地修复了这种七极真空管。
3. 3. The seven-pole vacuum tube is a crucial component in many electronic circuits.
   这种七极真空管是许多电子电路中的关键部件。