 
Summary: ME 413 Systems Dynamics & Control Chapter 6: Electrical Systems and Electromechanical Systems
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ChapterChapterChapterChapter 6666
ElectricalElectricalElectricalElectrical SystemsSystemsSystemsSystems andandandand
Electromechanical SystemsElectromechanical SystemsElectromechanical SystemsElectromechanical Systems
A. Bazoune
6.1 INTRODUCTION
The majority of engineering systems now have at least one electrical subsystem. This
may be a power supply, sensor, motor, controller, or an acoustic device such as a speaker. So
an understanding of electrical systems is essential to understanding the behavior of many
systems.
6.2 ELECTRICAL ELEMENTS
Current and Voltage Current and voltage are the primary variables used to
describe a circuit's behavior. Current is the flow of electrons. It is the time rate of change of
electrons passing through a defined area, such as the crosssection of a wire. Because
electrons are negatively charged, the positive direction of current flow is opposite to that of
electron flow. The mathematical description of the relationship between the number of
electrons ( called charge q ) and current i is
dq
i
