. Electrical measurement of instruments In this article, you will find the study notes on Measurement of Power, Energy, and Power Factor which will cover the topics such as Electric Power Measurements in DC & AC Circuits, Three Phase Power Measurement using Two Watt-meter, Measurement of Power Factor, Power Factor Triangle, Zero Cross Detection, Definition for non-sinusoidal current and sinusoidal voltage of power factor, Measurement of Energy, Electro-Mechanical induction type Energy meter, Electronic Energy meters, Smart Energy Metering & Energy Consumption Formula. Electric Power Measurements DC Electric Circuits In order to identify an electrical system in DC, a measurement of the electrical current, I, flowing through the bipoles and their electric voltage, V, across the terminals has to be formed. These measurements can be arranged by means of a DC ammeter and voltmeter. The electric power, P, related to such a bipole, can be defined as the