1 ASSIGNMENT 1 Textbook assignment: Chapter 1, “Introduction to Electron Tubes,” pages 1-1 through 1-55. _________________________________________________________________________________ 1-1.     The electrons emitted by a heated conductor come from what source? 1.    An external battery 2.    An external ac source 3.    Both 1 and 2 above 4.    The conductor itself 1-2.     What is another name for thermionic emission? 1.    The gap effect 2.    The heat effect 3.    The Edison effect 4.    The Fleming effect 1-3.     Electrons emitted by a hot filament are able to cross the gap between the filament and the plate. What force enables them to do this? 1.    Magnetic repulsion 2.    Inductive reactance 3.    Thermionic emission 4.    Electrostatic attraction 1-4.     Name the two series circuits that are associated with a diode electron tube. 1.    The plate and anode circuits 2.    The plate and filament circuits 3.    The battery and filament circuits 4.    The filament and cathode circuits 1-5.     When an ac voltage is applied across the plate and filament of a diode, the current measured will represent what type of waveform? 1.    Pulsating dc 2.    Dc 3.    Pulsating ac 4.    Ac 1-6.     A filament that uses a one-molecule- thick layer of barium and strontium is classified as what type of filament? 1.    Tungsten 2.    Oxide-coated 3.    Tungsten-strontium 4.    Thoriated-tungsten 1-7.     Which of the following ac filament voltages is most likely to be considered a common voltage? 1.    1.5 volts 2.    3.0 volts 3.    6.3 volts 4.    9.0 volts 1-8.     An ac directly heated filament has which of the following advantages? 1.    Even spacing relative to the plate 2.    Even emission across the filament 3.    Constant emission throughout the ac cycle 4.    Rapid heating effect 1-9.     An indirectly heated cathode always uses what material for its emitting surface?   1.    An oxide coating   2.    A thorium coating   3.    A tungsten coating   4.    A graphite coating