Summary: Explains the principle of the electromagnet and points out how it is used in doorbells, telephones, and electric motors. For elementary school science classes.
Credits: Adviser, Gerald S. Craig.
© Young America Films, Inc.; 30Sep49; MP4559.
ELECTRON THEORY. De Forest's Training, Inc., c1948. (Radio Electronics. Reel lesson 7)
Summary: Explains that all substances are composed of infinitely small atoms resembling our solar system, the central body being the positive nucleus and the outer revolving bodies being the negative electrons. Shows that when the atoms become negatively and positively charged a condition of unbalance exists, and the resulting flow of electrons, which tend to restore a balance, can produce usable energy.
© De Forest's Training, Inc.; 1Oct48; MP3900.
ELECTRONIC TUBES. De Forest's Training, Inc., c1948. 100 ft., b&w, 16mm. (Radio Electronics. Reel lesson 8)
Summary: Actions, functions, and characteristics of the vacuum tube. Shows that since the changes of grid voltage can be duplicated only by larger changes of plate voltage, the triode tube acts as an amplifier.
© De Forest's Training, Inc.; 1Oct48; MP3901.
ELÉCTRONS. Encyclopaedia Britannica Films, Inc., c1946. 1 reel, sd., 16mm.