| 323 / | HD | ELECTRICITY: POWER SUPPLY OR REGULATION SYSTEMS |
| 234 | DF | OUTPUT LEVEL RESPONSIVE {6} |
| 247 | DF | .~ Using a transformer or inductor as the final control device {5} |
| 249 | | .~.~ Controllably saturable {3} |
| 250 | DF | .~.~.~> With specific core structure (e.g., gap, aperture, slot, permanent magnet) |
| 251 | DF | .~.~.~> With plural power windings {2} |
| 254 | DF | .~.~.~> With electronic tube or a three or more terminal semiconductive device in control circuit |