Image: Mu metal CRT shields

Description: Magnetic shields for cathode ray tubes (CRTs) made of mu metal for use in oscilloscopes, from an ad by James Millen Mfg. Co. in a 1945 electronics magazine. The electron beams used in cathode ray tubes to draw on the tube's screen could be deflected by magnetic fields from transformers and other electronic components in the oscilloscope's insides. So the sides of the long CRT tube were surrounded by a shield made of mu metal. Mu metal is a high permeability nickel-iron alloy which could shield against magnetic fields by conducting the magnetic field lines around the shielded space.
Title: Mu metal CRT shields
Credit: Retrieved June 12, 2014 from Radio News magazine, Ziff-Davis Publishing Co., New York, Vol. 33, No. 3, March 1945, p. 12 on American Radio History site
Author: Unknown authorUnknown author
Permission: This image is from an advertisement for James Millen Mfg. Co. without a copyright notice published in a 1945 magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No