Stewart type 12-18-GC backward wave oscillator
date: label: date made
content: ca 1961
notes: label: Description (Brief)
content: A long thin glass tube with a metal cap on the bottom and six pins and an exhaust tip on top, one pin in the side. Donor’s card reads: “Backward wave oscillator made by Stewart Engineering Company, Santa Cruz, California. A backward wave oscillator is a self-oscillating travelling wave tube which is electrically tunable over a wide range of frequencies. This particular tube is capable of tuning from 12400 to 18000 megacycles. It consists of an evacuated enclosure containing an electron gun, precision lens for forming a hollow electron beam, a helix very accurately made and carefully placed, and an electron oscillator. External connections are made to each end of helix and to the conventional miniature type base. Heater: 6.3 volts at .64 ampere. Oscillation frequency is controlled by voltage applied to the helix, 400 volts giving a frequency of about 12000 megacycles, and 200 volts will give about 18000 megacycles. Power output is continuously adjustable to zero by varying the beam current which is adjusted by varying the anode or grid voltages. Magnetic field to surround the tube to have a uniform 800 gauss strength for a distance of over 2.5 inches around the helix. Maximum power at 17000 megacycles with 12.6 milliamps at 210 volts on the cathode, is 68 milliwatts. Tube cost in 1961 is $1000.”
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Paul G. Watson
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.325307
label: catalog number
content: 325307
label: accession number
content: 252994
objectType: label: Object Name
content: Traveling Wave Tube
label: Other Terms
content: Traveling Wave Tube; Electron Tubes
physicalDescription: label: Measurements
content: overall: 6 3/4 in x 1 in; 17.145 cm x 2.54 cm