ELERICAL APPARATUS-NAMELY, AUDIO AND RADIO GENERATORS, OSCILLATORS, DETECTOR ASSEMBLIES AND CIRCUITS, RECTIFIERS AND DIRECT AND ALTERNATING-CURRENT AMPLIFIERS; VOLTAGE, CURRENT AND ELECTRONIC POWER-SUPPLY SYSTEMS; VIBRATION PICK-UPS FOR GENERATING VOLTAGES IN RESPONSE TO MECHANICAL VIBRATIONS; AUDIO-FREQUENCY AND RADIO-FREQUENCY TRANSFORMERS; CONNECTORS, INSULATORS, BINDING POSTS, SWITCHES, CONTACTORS, CONTACT MEMBERS, KNOBS, SOCKETS, RHEOSTATS, POTENTIOMETERS FOR USE IN RADIO AND SIMILAR APPARATUS, RESISTORS, ATTENUATORS AND VOLTAGE DIVIDERS; CAPACITORS, INDUCTORS AND CHOKES; ELECTRIC AND ELECTRONIC CONTROL BOXES AND MOTOR-SPEED CONTROL CIRCUITS; RADIO AND OTHER DIALS FOR USE ON ELECTRICAL COMPONENTS AND INSTRUMENTS; ELECTRO-MECHANICAL HUMMER OSCILLATORS; PIEZOELECTRIC CRYSTALS; ELECTRIC FILTERS; ELECTRIC CABLES; CATHODE-RAY TUBES; TRANSMISSION-LINE PHASE, INSERTION AND TERMINAL UNITS; AND TUNED ELECTRIC CIRCUITS FOR SUPPRESSING HARMONICS AND OTHER FREQUENCY COMPONENTS, NOISE AND HUM.

STANDARD UNITS OF RESISTANCE, INDUCTANCE AND CAPACITANCE FOR USE IN ELECTRIC MEASURING CIRCUITS; ELECTRICAL BRIDGE CIRCUITS OF THE DECADE, SLIDE-WIRE, DISSIPATION-FACTOR, VACUUM-TUBE-CHARACTERISTIC, CAPACITANCE RESISTANCE AND INDUCTANCE TYPES AND ACCESSORY ELECTRIC CIRCUITS AND COMPONENTS REQUIRED FOR OPERATION WITH THE BRIDGE CIRCUITS; VOLTAGE METERS, OHMMETERS, d'ARSONVILLE METERS, GALVANOMETERS, WAVEMETERS, METERS FOR MEASURING CAPACITY IMPEDANCE, MODULATION, SOUND - LEVEL, NOISE, VIBRATION, DISTORTION, RATE, AUDIBILITY, FREQUENCY AND POWER, AND METERS OF THE HOT-WIRE, HETERODYNE AND OTHER TYPES AND ACCESSORY ELECTRIC CIRCUITS AND COMPONENTS REQUIRED FOR OPERATION WITH THE METERS; ELECTRIC INTERPOLATION APPARATUS; INDUSTRIAL ELECTRONIC STROBOSCOPIC AND OTHER INSTRUMENTS-NAMELY, MOTION-PICTURE RECORDING APPARATUS AND FRAMES, CAMERAS, TRIPODS, INSTRUMENT - CARRYING CASES, LENSES AND ELECTRIC FLASH LAMPS; WAVE-FORM VIBRATION, AND SOUND MEASURING INSTRUMENTS AND ANALYZERS; CALIBRATION, VACUUM-TUBE AND OTHER PRECISION FORKS; VOLTAGE AND CURRENT MULTIPLIERS; SPECIAL MEASURING INSTRUMENTS FOR MAKING MEASUREMENTS AT AUDIO AND RADIO FREQUENCIES; MEASURING NETWORKS; STANDARD-SIGNAL GENERATORS AND OSCILLATORS; OSCILLOSCOPES, GAMMA-RAY AND BETA-RAY COUNTERS; FREQUENCY STANDARDS AND MONITORS; AND RANGE-EXTENSION UNITS.