21 ELECTRONIC AND ELECTRICAL CIRCUITS-NAMELY, ELECTRONIC CONTROLS FOR MOTOR-DRIVEN SUPPORTS FOR CAMERAS, ELECTRONIC CONTROLS FOR MOTOR-DRIVEN ZOOM LENSES, ELECTRONIC SWITCHERS FOR SELECTIVE USE OF TELEVISION CAMERAS, INCLUDING AUTOMATIC AND MANUAL SEQUENCE SWITCHERS; AND MOTOR DRIVES-NAMELY, MOTOR-DRIVEN DRIVES FOR SUPPORTS FORTELEVISION CAMERAS, AND MOTOR DRIVVES FOR ZOOM LENSES