335 / | HD | ELECTRICITY: MAGNETICALLY OPERATED SWITCHES, MAGNETS, AND ELECTROMAGNETS |
209 | DF | MAGNETS AND ELECTROMAGNETS {10} |
220 | DF | .~ With magneto-mechanical motive device (e.g., electromagnet with armature) {21} |
253 | .~.~ With armature latch means (e.g., means to retain armature in open or closed position {1} | |
254 | DF | .~.~.~> With latch-control winding |