I. PMMC and Wattmeter A. What is a PMMC? A PMMC (Permanent Magnet Moving Coil) instrument is an electrical measurement device used to measure current, voltage, resistance, and other electrical parameters. It operates on the principle of the interaction between a permanent magnet field and a moving coil, producing a torque proportional to the current being … [Read more...] about PMMC and Wattmeter: An In-Depth Explanation of Electrical Measurement Instruments