Swett & Lewis Gehrcke Cathode Glow Oscillograph
Oscillographe de Gehrcke
Glimmlicht-Oszillograph nach Gehrcke
In 1896, G. A. Frye began making X-ray tubes, which in 1897 was purchased by Swett & Lewis as the
first merger in the X-ray business. In 1901, the Western Electric Coil Co. was formed. In 1902 MacAlaster & Wiggin
purchased the X-ray tube business of Swett & Lewis. In 1916, the first significant merger took place, Scheidel Western,
Snook-Roentgen, MacAlaster & Wiggin, and Victor Electric Co. were merged with Victor, the surviving name.
Four years later, in 1920, a second major merger was accomplished when Victor was acquired by General Electric, which was,
at that time, the foremost manufacturer of X-ray tubes.
A precursor to the modern oscilloscope, an apparatus built in the early 1900s for the visual study of
alternating current characteristics. In operation, the cathode is covered for part of its length with a blue glow,
the coverage depending on the applied voltage. The distance that the glow extends along the electrode is a function
of the instantaneous value of the potential of the electrode. When an alternating potential difference of 750 to 1500
volts is used, and the electrodes are viewed in a rotating mirror, the potential wave form is clearly seen.
THE GLOW-LIGHT OSCILLOGRAPH, by P. M. Dysart
Longueur • Length • Länge : 115 mm • 4" 1/2
Diamètre • Diameter • Durchmesser : 12 mm • 1/2"
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