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ID = 77937
Tube type:  SPECIAL TUBE, other or unknown 
  Ca. 1925 up to 1945 very rare. ***
Identical to CRT-Probe

Base Octal (Int.Octal, IO) K8A, USA 1935
Was used by Technology / Measurement
Filament Indirect

No code or manufacturer can be read on this tube. Nevertheless it closely recalls the cathode ray tube designed by RCA to explore the magnetic field distribution over wide spaces. This device was described in the attached pdf from Electronics, July 1938.

This sample looks to be very similar to the one in the article, but for the octal base.

Operation is based upon the deflection of a tiny electron beam in a magnetic field, so to follow curved trajectories and impinge the metal dish somewhere on its surface. The beam trajectory is made visible by a small quantity of argon inside the bulb. Concentric rings engraved on the dish surface allow a quick evaluation of the field strength.

Direction and intensity of a magnetic field, as well its spatial distribution, can be rapidly evaluated when using a probe with this kind of sensor.


Just Qvigstad

Collection of

Documents about this component
  Electronic device for measuring magnetic fields, Electronics, July 1928 1717 KB


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