Rongge

2.3 Occupational Information Network Key Points 1.         The four major groups of occupations in the field of electrical engineering are: a.         Power engineering b.        Electrical installations engineering c.         Communications electronics engineering d.        Industrial electronics engineering. 2.         Across the network of technical occupations, the following personnel cadre are employed: a.         Artisan b.        Craftsman c.         Technician d.        Engineer. 3.         An artisan is an accomplished operator with a comprehensive knowledge of techniques and the tools used in his or her area of special...

5.9 How electricity is generated Key points 1. A D.C. generator produces a unidirectional voltage and current. 2. The three major parts of a D.C. generator are stator, rotor and commutator. 3. The direction of the induced e.m.f. in straight conductor is determined by the Right-Hand Rule. 4. The direction of the induced e.m.f. in coil conductor or solenoid is determined by the Right-Hand Grip Rule. 5. Electrical energy may be generated by ways other than magnetism and chemical action. 6. A piece of electric crystal can generate electricity when subjected to a changing pressure across two of its sides (compressed or released). 7. A steady pressure applied to a piece of electric crystal will not generate electricity. 8. The most frequently used piezoelectric crystals are quartz, Rochelle salt and barium titanate. 9. Electricity is produced whenever there is a relative motion between two materials such as a glass rod and silk. This is called static electricity. We can simply say t...