| 323 / | HD | ELECTRICITY: POWER SUPPLY OR REGULATION SYSTEMS |
| 304 | DF | SELF-REGULATING (E.G., NONRETROACTIVE) {2} |
| 311 | DF | .~ Using a three or more terminal semiconductive device as the final control device {1} |
| 312 | DF | .~.~ For current stabilization {2} |
| 315 | DF | .~.~.~ Including parallel paths (e.g., current mirror) {2} |
| 316 | | .~.~.~.~ With amplifier connected to or between current paths |