A sealed enclosure, either highly evacuated or containing a controlled quantity of gas, in which electrons can be made sufficiently mobile to act as the principal carriers of current between at least one pair of electrodes.电子管：一种密闭的容器，或真空或包含一定的气体介质， 在其内电子能迅速移动以作为至少一对电极间的主要电流载体