. The Bell System technical journal . of the order of 70 volts. The glow discharge initiallycovers the entire cathode area. Local heating occurs and some parts ofthe oxide coating begin to emit electrons thermionically. This local emis-sion causes increased current density and further increases the localheating. The discharge thus concentrates to a thermionic arc coveringonly a portion of the coil. The sustaining voltage is then of the order of10 volts. Mechanically the tube was designed to minimize the possibility of ashort circuit resulting from structural failure of tube parts. Fig. 16 show
. The Bell System technical journal . of the order of 70 volts. The glow discharge initiallycovers the entire cathode area. Local heating occurs and some parts ofthe oxide coating begin to emit electrons thermionically. This local emis-sion causes increased current density and further increases the localheating. The discharge thus concentrates to a thermionic arc coveringonly a portion of the coil. The sustaining voltage is then of the order of10 volts. Mechanically the tube was designed to minimize the possibility of ashort circuit resulting from structural failure of tube parts. Fig. 16 showsthe construction of the tube. The glass envelope and stem structure whichhad previously been developed for the hot cathode repeater tubes wereused as a starting point for the design. The anode is a circular disk ofnickel attached to two of the stem lead wires. To provide shock resistancethe supporting stem leads are crossed and welded in the center. To pro-tect against weld failure, a nickel sleeve is used at each end of the cathode.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
