Notebook

        M.I instruments are mainly used for the measurement of alternating currents and voltages, though it can also be used for d.c measurements.        The general principle of a M.I instrument can be explained under;            Let...

   These instruments are used either as ammeters or voltmeters and are suitable for d.c work only. PMMC instruments work on the principle that, when a current carrying conductor is placed in a magnetic field, a mechanical force acts on the conductor. The current carrying coil, placed in magnetic field is...

Types of instruments (1) Permanent Magnet Moving Coil (PMMC) instruments . (2) Moving iron instruments. (3) Electrodynamometer instruments. (4) Thermal instruments (5) Induction instruments. (6) Electrostatic type instruments. (7) Rectifier type instruments.     The PMMC (adsbygoogle...

            An indicating instrument essentially consists of a moving system pivoted in jewel bearings. A pointer is attached to the moving system which indicates the electrical quantity to be measured, on a graduated scale. In order to ensure the proper operation...

Standards and their classification             A standard is a physical representation of a unit of measurement. It is a piece of equipment having a known measure of physical quantity. They are used for the measurements of other physical quantities by comparison...