1-3 electric circuits

8/10/2019 1-3 Electric Circuits

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Tradecraft University Basic Electricity 101

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1.3 The Essential Electric Circuit

We need a defini tion fo r circuit

Electrical current must have a source (battery,

generator, city grid etc.), a conductive path (wires or other conductors

intentional ornot, a load (light bulb or other user of the power), and a return path to the source to bedefined as . In essence, a circuit is not a circuit unless what leaves thea practical circuit source finds its way back to the source. If there is a break in the electrons journey thereis no useful purpose as the load(in this case a light bulb) cannot produce light. In the

picture, we have installed an intentional break in the circuit we call it . a switch You might have been wondering how electrons can continuously flow in a uniformdirection through wires without the benefit of these hypothetical electron Sources andDestinations.In order for the Source-and-Destination scheme to work, both would have to have aninfinite capacity for electrons in order to sustain a continuous flow! Using the marble-and-tube analogy, the marble source and marble destination buckets would have to beinfinitely large to contain enough marble capacity f or a flow of marbles to be sustained.

The answer to this paradox is found in the concept of a circuit : a never-ending loopedIf we take a wire, or many wires joined end-to-end, and loop itpathway for electrons.

around so that it forms a continuous pathway, we have the means to support a uniformflow of electrons without having to resort to infinite Sources and Destinations:


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Each electron advancing clockwise in this circuit pushes on the one in front of it, whichpushes on the one in front of it, and so on, and so on, just like a hula-hoop filled withmarbles.

Now, we have the capability of supporting a continuous flow of electrons indefinitelywithout the need for infinite electron supplies and dumps. All we need to maintain thisflow is a continuous m eans of motivation for those electrons, which well address in thenext section of this chapter.

It must be realized that continuity is just as important in a circuit as it is in a straight. Just as in the example with the straight piece of wire between the electronpiece of wire

Source and Destination, any break in this circuit will prevent electrons from flowingthrough it:


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An important principle to realize here is that .it doesnt matter where the break occurs

Any discontinuity in the circuit will prevent electron flow throughout the entire circuit.

Unless there is a continuous, unbroken loop of conductive material for electrons to flowthrough, a sustained flow simply cannot be maintained.

REVIEW:

A is an unbroken loop of conductive material that allows electrons to flowcircuitthrough continuously without beginning or end. If a circuit is broken, that means its conductive elements no longer form a complete path, and continuous electron flow cannot occur in it. The location of a break in a circuit is irrelevant to its inability to sustain continuouselectron flow. Any break, anywhere throughout thein a circuit prevents electron flowcircuit.

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1-3 electric circuits

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