AMMETER, MEASURING TRANSFORMER, PRECISION RESISTOR FOR MEASURING PURPOSES, VOLTMETER, FREQUENCY METER, WATTMETER, POWER FACTOR METER, MULTIMETER, OHMMETER, BRIDGE INSULATION AND EARTH TESTER, CABLE TRACER, LINE RECORDER, CHOPPER BAR RECORDER, POTENTIOMETRIC RECORDER, CONTROLLER, COMPENSATOR, TELEMETERING CONVERTER, D. C. TO D. C. CONVERTER, ILLUMINATION METER, PHOTO-ELECTRIC EXPOSURE METER