Electrical measurements course introduces the basic principles of all measuring instruments. It also deals with the measurement of RLC parameters voltage, current Power factor, power, energy and magnetic measurements.
electrical measurements and measuring instruments by golding and widdis pdf free download
Preamble: This course introduces the principle of operation of basic analog and digital measuring instruments for measurement of current, voltage, power, energy etc. Measurement of resistance, inductance and capacitance by using bridge circuits will be discussed in detail. It is expected that student will be thorough with various measuring techniques that are required for an electrical engineer.
We adapted a permanent magnet moving coil instrument (PMMC) (Golding and Widdis 1963; Paul 1978; Stanek 1961) as actuator and sensor. PMMCs were used for sensitive and precise electrical measuring instruments until the technology was superseded by modern electronic instruments in the 1980s. In a PMMC, a coil rotates in a small circular gap between two pole pieces of a permanent magnet and a soft iron cylinder. The magnetic field in the gap is radial uniform and always perpendicular to the direction of movement of the coil. The torque induced is thus only dependent on the current through the coil but not on the angle of deflection. The strength of the magnetic field is determined by the geometry of the gap and the strength of the permanent magnet, neither change during the test. We only have to control and measure the electric current through the coil. 2ff7e9595c
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