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alternating current amplification applied voltage atom audion becomes capacity cathode and anode Chapter characteristic condenser condition constant contact potential difference curve decrease depends detecting current detector device discharge effect electric field electron affinity electron emission emitted electrons equal expressed filament and grid gases gives grid potential half period heating high frequency increase inductance input circuit input voltage ionization by collision J. J. Thomson large number load resistance maximum mean free path measured mercury vapor metallic modulated mutual conductance necessary negative with respect number of electrons obtained operation oscillation oscillation circuit output circuit Phys plate circuit plate current plate potential plate resistance plate voltage positive ions potential difference pressure radiated reactance receiver shunt rectified result saturation current shown in Fig slope space charge substance surface telephone temperature thermionic devices thermionic efficiency thermionic emission thermionic tubes thermionic valve tion tungsten vacuum tube voltage drop volts wave wire zero
Page 14 - An electromagnetic wave in space has both an electric and a magnetic field intensity which are at right angles to each other and to the direction of propagation of the wave. The two field intensities are related to each other by &
Page 250 - CR tube in detail, it will be noted that the principle is basically the same as that of the thermionic valve. The source of electrons is a filament, or indirectly heated cathode, which is surrounded by a metal tube, shield, grid or Wehnelt cylinder as it is variously termed. The grid is maintained at a negative potential with respect to the cathode and therefore has the effect of repelling the electrons and tending to concentrate them. A short distance from the cathode is the anode, comprising a...
Page 32 - ... m is the mass of the electron, and n is the number of electrons per cubic centimeter outside the surface.
Page 149 - When Ec is positive some of the electrons moving toward the grid are drawn to the grid, while the rest are drawn through the openings of the grid to the anode under the influence of E,. The relative number of electrons going...
Page 224 - In the early part of this chapter it was pointed out that the valence of an element varies according to the character of the elements with which it combines.
Page 50 - ... discussion of the extensive investigations that have been carried out on thermionics, but merely touch upon those phases of the subject which have a direct bearing on the theory of operation of the thermionic amplifier. Consider a structure consisting of a heated cathode and an anode, and contained in a vessel which is evacuated to such an extent that the 1 In this connection it may be stated that the most reliable gauge for the measurement of high vacua is the so-called "ionization manometer"...
Page 62 - Here the voltage is not high enough to draw all the electrons to the anode as fast as they are emitted from the cathode...
Page 375 - Section 36 that if the gas pressure in a tube is so low that the mean free path of the electrons in the gas is large compared with the distance between the electrodes...
Page 31 - Electrons, Conduction — The electrons in the conduction band of a solid, which are free to move under the influence of an electric field.