Fundamental Electrical and Electronic Principles, Third Edition

138 Fundamental Electrical and Electronic PrinciplesSuggested Practical AssignmentsNote: These assignments are qualitative in nature.Assignment 1Apparatus:Method:To compare the effectiveness of different magnetic core materials.1 coil of wire of known number of turns1 d.c. psu1 ammeter1 set of laboratory weights1 set of different ferromagnetic cores, suitable for the coil used.1 Connect the circuit as shown in Fig. 4.23 .2 Adjust the coil current carefully until the magnetic core just holds thesmallest weight in place. Note the value of current and weight.3 Using larger weights, in turn, increase the coil current until each weight isjust held by the core. Record all values of weight and corresponding current.4 Repeat the above procedure for the other core materials.5 Tabulate all results. Calculate and tabulate the force of attraction and mmf ineach case.6 Write an assignment report, commenting on your findings, and comparingthe relative effectiveness of the different core materials.coreAId.c.p.s.u.NweightFig. 4.23Assignment 2Apparatus:To plot a magnetisation curve, and initial section of a hysteresis loop, for amagnetic circuit.1 magnetic circuit of known length, and containing a coil(s) of known numberof turns1 variable d.c. psu1 Hall Effect probe1 ammeter1 DVM