| 361 / | HD | ELECTRICITY: ELECTRICAL SYSTEMS AND DEVICES |
| 139 | DF | CONTROL CIRCUITS FOR ELECTROMAGNETIC DEVICES {7} |
| 160 | DF | .~ For relays or solenoids {11} |
| 166 | DF | .~.~ Plural relays or solenoids sequentially operated {2} |
| 168.1 | DF | .~.~.~ Pulse responsive {1} |
| 169.1 | ![]() | .~.~.~.~ Including electronic element |