Primary and Secondary Group Identification

Students read descriptions of the voltage, current, and turns ratios of the primary and secondary coils for a transformer in this interactive lesson.

Learners view the waveforms and voltages of an Edison Three-Wire System and read a description of the polarities across the secondary of the center-tap transformer. This transformer supplies power to residential homes.

Students read about the different kinds of economic interest groups including business and trade associations, labor unions, agricultural organizations, and professional associations.