has a unique set of such characteristic curves. The curves graphically relate the changes to the instantaneous plate current driven by a much smaller change in the grid-to-cathode voltage () as the input signal varies. The V-I characteristic depends upon the size and material of the plate and cathode. Express the ratio between voltage plate and plate current. V-I curve (Voltage across filaments, plate current) Plate current, plate voltage characteristics DC plate resistance of the plate—resistance of the path between anode and cathode of direct current AC plate resistance of the plate—resistance of the path between anode and cathode of alternating current Size of electrostatic field Size of electrostatic field is the size between two or more plates in the tube. Patents —Instrument for converting alternating electric currents into continuous currents (Fleming valve patent) —Device for amplifying feeble electrical currents —de Forest's three electrode Audion See also Bogey value—close to manufacturer's stated parameter values Fetron—a solid-state, plug-compatible, replacement for vacuum tubes List of vacuum tubes—a list of type numbers. List of vacuum-tube computers Mullard–Philips tube designation Nixie tube—a gas-filled display device sometimes misidentified as a vacuum tube RETMA tube designation RMA tube designation Russian tube designations Tube caddy Tube tester Valve amplifier Zetatron References Further reading Eastman, Austin V., Fundamentals of Vacuum Tubes, McGraw-Hill, 1949 Millman, J. & Seely, S. Electronics, 2nd ed. McGraw-Hill, 1951. Philips Technical Library. Books published in the UK in the 1940s and 1950s by Cleaver Hume Press on design and application of vacuum tubes. RCA. Radiotron Designer's Handbook, 1953 (4th Edition). Contains chapters on the design and application of receiving tubes. RCA. Receiving Tube Manual, RC15, RC26 (1947, 1968) Issued every two years, contains details of the technical specs of the tubes that RCA sold. Shiers, George, "The First Electron Tube", Scientific American, March 1969, p. 104. Stokes, John, 70 Years of Radio Tubes and Valves, Vestal Press, New York, 1982, pp. 3–9. Thrower, Keith, History of the British Radio Valve to 1940, MMA International, 1982, pp 9–13. Tyne, Gerald, Saga of the Vacuum Tube, Ziff Publishing, 1943, (reprint 1994 Prompt Publications), pp. 30–83. Basic Electronics: Volumes 1–5; Van Valkenburgh, Nooger & Neville Inc.; John F. Rider Publisher; 1955. Wireless World. Radio Designer's Handbook. UK reprint of the above. "Vacuum Tube Design"; 1940; RCA. External links The Vacuum Tube FAQ—FAQ from rec.audio The invention of the thermionic valve . Fleming discovers the thermionic (or oscillation)