| 361 / | HD | ELECTRICITY: ELECTRICAL SYSTEMS AND DEVICES |
| 139 | DF | CONTROL CIRCUITS FOR ELECTROMAGNETIC DEVICES {7} |
| 160 | DF | .~ For relays or solenoids {11} |
| 170 | | .~.~ Condition responsive (e.g., external circuit condition) {9} |
| 171 | DF | .~.~.~> Code responsive {1} |
| 173 | DF | .~.~.~> Light {3} |
| 178 | DF | .~.~.~> Fluid (e.g., liquid level, humidity) |
| 179 | DF | .~.~.~> Proximity or contact {2} |
| 182 | DF | .~.~.~> Frequency (e.g., audio, radio) {2} |
| 185 | DF | .~.~.~> Phase |
| 186 | DF | .~.~.~> Pulse |
| 187 | DF | .~.~.~> Voltage or current level discriminators |
| 188 | DF | .~.~.~> Variable impedance |