The 792A AC/DC Transfer Standard is a laboratory standard instrument that calibrates ac voltage calibrators, ac/dc transfer standards, and ac voltmeters. It consists of four main components: a transfer standard sensor unit (called the transfer standard in this manual), power pack, 1000V range resistor, and transfer switch. Inputs are accepted in the range 2 mV to 1000V rms, 10 Hz up to 1 MHz, with a maximum Volt-Hertz product of 10 The 792A compares the heating effect of an ac voltage with that of a known dc voltage (or other ac voltage). Sensing the rms value is done entirely without thermocouples and the drawbacks that accompany them. (See The Fluke RMS Sensor, paragraph 1-3, for more information.) The transfer standard accepts dc and ac voltages through a stainless steel Type “N” INPUT connector and presents a dc voltage at the front panel DC OUTPUT binding posts that is linearly proportional to the rms potential of the input. A digital voltmeter of 6V4-digit resolution or better can be used to resolve the 2.0V nominal full-scale output. An OVERLOAD indicator and beeper warns of input overloads. Even though the transfer standard is protected electronically from overloads, it is a delicate laboratory instrument and should be treated with extreme care. Before operating the transfer standard, be sure to read Sections 2 and 3, particularly the WARNING that explains the restriction to use only sources that are current-limited to 200 mA or less (at the beginning of Section 2), and the CAUTION about observing the voltage protection level limits for each INPUT RANGE setting.