Abstract: An electronic apparatus for automatically zeroing or nulling an analog offset voltage by using multiple bit successive approximation to generate an analog zeroing voltage of equal magnitude and opposite polarity to that of the offset voltage, and then summing the zeroing voltage with the offset voltage.

Abstract: A high power source load simulator presents itself to a power meter as a conventional electrical load, but in fact is highly portable and dissipates relatively little power and heat. A current source generates a selectively variable current signal which is characterized by a relatively low, constant voltage. A voltage source generates a selectively variable voltage signal which is phase locked with the current signal and is characterized by a relatively low, constant current. The phase angle between the two signals is selectively variable by means of a phase shift network interposed mediate the voltage and current sources. The current and voltage signals are impressed upon the current and voltage sensing inputs of a power monitor via jumper cables. An AGC circuit is also interposed between the voltage and current sources to insure the amplitude independence of their respective signals.