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| [[Category:Done 2015-09-05]] | | #REDIRECT [[electric circuit]] |
| [[File:Closed ciruit example.jpg|thumb|right|Figure 1: An example of a closed circuit (click to enlarge).<ref name=C>University of Colorado (2011). Circuit Construction Kit (DC Only), Virtual Lab [Online]. Available http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc-virtual-lab</ref>]]
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| <onlyinclude>An '''electric circuit''' is a connection of components that can conduct [[current]]. Simple electrical circuits have conductors (usually [[wire]]s), a component that supplies [[power]] (like a [[battery]] or [[wall plug]]) and a component that absorbs power called the load. A light bulb would be an example of a load and there must always be a return path - a way for the electrons to come back to the power source from the load.</onlyinclude> Every circuit is designed to deliver power to one or more loads. For example, in a boombox the power goes to the speakers. In the same way, in a lamp the power goes to the light-bulb. The circuit allows the [[charge]] to leave from one side of the power supply and come back on the other side of the power supply.
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| Circuits can be in [[Series circuit|series]], [[Parallel circuit|parallel]] or a combination of the two referred to as a series-parallel circuit.<ref name=A>R.T. Paynter, “Basic Electric Components and Meters,” in ''Introduction to Electricity'', 1rst ed. NJ: Prentice-Hall, 2011, ch. 4, sec. 4.3, pp. 155-160.</ref> To read more on these differing circuit layouts, visit: [[series circuit]] and [[parallel circuit]].
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| In Figure 1, the circuit is closed (the charge can leave from the supply, go through the light bulb and come back to the supply) and the light-bulb acts as the load. Notice that the [[voltmeter]] reading displays 0 [[volt|V]] because there is 0 [[voltage|voltage drop]] across the [[switch]].<ref name=C />
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| ==Open circuit==
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| [[File:Open circuit example.jpg|thumb|right|Figure 2: An example of a open circuit (click to enlarge).<ref name=C>University of Colorado (2011). Circuit Construction Kit (DC Only), Virtual Lab [Online]. Available http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc-virtual-lab</ref>]]
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| An open circuit (like the one in Figure 2) has a physical break in the conduction path where [[current]] drops to 0 and [[resistance]] becomes infinite (far too high for an [[Multimeter#Ohmmeter|ohmmeter]] to measure). [[Voltage]] however can be measured because the [[Multimeter#Voltmeter|voltmeter]] connects across the open terminal.<ref name=B>R.T. Paynter, “Basic Electric Components and Meters,” in ''Introduction to Electricity'', 1rst ed. NJ: Prentice-Hall, 2011, ch. 4, sec. 4.4, pp. 160-162.</ref> Note the open circuit is not a true circuit because the charge from one side of the power supply can't leave and come back to the other side of the power supply.
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| In Figure 2, the switch is lifted therefore opening the circuit meaning the current does not have a complete path and the light-bulb does not function. The voltmeter can still be connected and displays a reading of 18 [[volt]]s due to the presence of the two 9 V batteries in [[Series circuit|series]].<ref name=C />
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| ==Short circuit==
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| [[File:Short circuit example.jpg|thumb|left|Figure 3. An example of a short circuit, (click to enlarge).<ref name=C>University of Colorado (2011). Circuit Construction Kit (DC Only), Virtual Lab [Online]. Available http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc-virtual-lab</ref>.]]
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| A short circuit (shown in Figure 3) is an unintentional low [[resistance]] connection between two or more points in a circuit. Because current increases as the resistance drops (given by [[Ohm's law]]), this will result in a large amount of current flowing through the "short." This higher current, if it is greater than the [[wire gauge]] can safely handle, has the potential to burn the current path due to high [[temperature]]s, and could cause a fire. This results in ''shorting'' the circuit.<ref name=B /> Safety devices such as [[fuse]]s and [[circuit breaker]]s are used in the case of a short circuit to prevent the [[shock hazard]]s and damage associated with it.
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| In Figure 3, a short circuit is present. Although some of the current still goes through the light-bulb, the path bypassing the light-bulb offers the lowest resistance for the circuit. This lower resistance equates to a significantly larger current. This high amount of current surpasses the current rating of the wire thereby destroying the switch and burning part of the current path.<ref name=C />
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| ==References==
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| {{reflist}}
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| [[Category:Uploaded]] | |