The thermionic vacuum tube and its applications (1920)
Van der Bijl, Hendrik Johannes, 1887- · New York McGraw-Hill Book, Co · leaf 267
Fig. 131. Fig. 132. account of their low vapor pressure, the refractory metals such astungsten and molybdenum are very suitable materials for use inhigh-power tubes. Tungsten can, for example, be heated duringevacuation to about 2500° K. to drive out occluded gases, whileduring operation the…
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