How many kinds of electric circuits do you think there are? To know how to answer this question means knowing what an electric circuit is. Begin by examining the word “circuit:”
cir·cuit
[sur-kit]–noun
1. an act or instance of going or moving around.
2. a circular journey or one beginning and ending at the same place; a round.
3. a roundabout journey or course.
4. a periodical journey from place to place, to perform certain duties, as by judges to hold court, ministers to preach, or salespeople covering a route.
5. the persons making such a journey.
6. the route followed, places visited, or district covered by such a journey.
7. the line going around or bounding any area or object; the distance about an area or object.
8. the space within a bounding line; district: the circuit of the valley.
Do you see what these definitions have in common? If you said “goes around,” you are correct. A circuit involves leaving a point, going on a trip along a defined course, and returning to the original point.
Now, lets be a little more specific. What is an “electric circuit?” Then we have just one definition, but it has two parts:
Electricity .
a. Also called electric circuit. the complete path of an electric current, including the generating apparatus, intervening resistors, or capacitors.
b. any well-defined segment of a complete circuit.
So now you know what an electric circuit is. The apparatus, equipment or device that supplies the electricity can be a generator, a battery, a capacitor or even static electricity. In other words, anything that causes electrons to flow from one point to another will drive an electric circuit. A resistor is – strangely enough – anything that resists the flow of electricity as it goes around the circuit. It can be an electric heater, a light bulb, a motor or anything that draws energy from the flow of electrons and converts it into work, heat, light or other form of energy. A capacitor stores electrons and can discharge them upon demand.
What the definition failed to include is the fact that a conductor is necessary, too. A conductor is anything that allows the electrons to flow. It usually is a metal wire – metals conduct electricity. But it can also be a pool of salt water, a carbon rod or charged particles such as anions and cations. (We will talk about these at another time.)
To keep the metal wire from conducting electricity to things we don’t want to be involved in our circuit, we need an insulator. This is something coating the wire that does not conduct electricity. Rubber is a great insulator and it is commonly used.
There are just two types of electric circuits: a series circuit and a parallel circuit. The series circuit means that two or more devices are connected – or “wired” – together one after the other. The parallel circuit means that the two or more devices are connected to the source of electricity independently. Look at the illustrations. Which one is which? Point out the series diagram and the parallel circuit.
By the way, notice some of the symbols used. The pairs of short/long parallel lines represent a battery. The “+” is the positive terminal, or cathode. The “-“ is the negative terminal, or anode. In a circuit, electrons flow through the conductor from the anode to the cathode.
After you understand the fundamentals of electric circuits, you are armed with knowledge. For example, you know that if an insulator is placed in the path of a circuit, electrons will not flow. You may observe it, in which case we call it a conclusion. Or you may hypothesize that no electrons will flow. Then we say you are basing your idea on research about electrical phenomena that other people have conducted. If you actually observe how the circuit works, then you are producing a theory of your own.
No comments:
Post a Comment