Presentation On Basic Electrical Circuit Theory - PDF

Electric circuits or networks are the assemblage of devices and or equipment needed to connect the source of energy to the user or the device which exploits it. Communications systems, computer systems and power systems all consist of more or less complicated electric circuits which themselves are made up of a number of circuit elements. The devices and equipment mentioned above may be represented by ‘equivalent circuits’ consisting of these circuit elements, and an equivalent circuit must behave to all intents and purposes in the same way as the device or equipment which it represents. In other words, if the device were put into one ‘black box’ and the equivalent circuit were put into another ‘black box’, an outside observer of the behavior of each would be unable to say which black box contained the real device and which contained the equivalent circuit. In practice it is virtually impossible to achieve exact equivalence.


What is an Electric Circuit?
In the simplest terms, an electric circuit is a pathway for an electric current to flow from one point to another. From a high level, every circuit has three basic components:
Voltage source
Conductive path
A Load

Voltage Source
A voltage source introduces energy into a circuit via a potential difference between its positive (+) and negative (–) terminals. Voltage sources can be AC or DC–the main difference being how the current flows. AC sources produce voltages that vary sinusoidally, i.e. the current reverses direction periodically. Examples are power from the grid or generators. On the other hand, DC sources produce current that flows in one direction. Batteries are a source of DC voltage.

Conductive Path
A conductive path (aka a conductor) provides a medium for current flow through a circuit. These components have a very low resistance to current, e.g., copper wires, lead solder, or metallic traces on a printed circuit board (PCB). Conductors also help link other components together to achieve a single function.

Load
A load is any device that consumes power in a circuit. It can be anything from a light-emitting diode (LED) to a motor or siren. During a short circuit, the load is the conductor itself which generates heat, dissipating electric power.

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