Any person, if he, of course, did not refusefrom the blessings of civilization, is surrounded by many electrical devices. Far behind the examples you do not need to go: TV, telephone, the most ordinary incandescent lamp, etc. The basis of all such devices is the electric circuit. Many literary sources give similar definitions, however, with reference to the simplest variety. Why is it so, because modern electronic devices are so complicated that they are trusted by computerized systems? Indeed, strange, especially if we recall the central processors of personal computers with their millions of transistors - they also have an electric DC circuit. The reason for the above simplification of the definition is that any, even the most complicated, electrical circuit can be represented in the form of a large number of elementary components. By the way, this is why it becomes possible to perform the necessary calculations using known formulas.
So, with a simple and difficult to decide.Now let's explain what an electrical circuit is. In order to be more clear, let's consider the simplest example - an electric flashlight. And not the one in which the control microcircuit is used (switching modes, flashing, etc.), and the most common - with a battery, a light bulb and an activation tumbler. It consists of a housing in which the light source itself is located, a switch, a battery compartment with two contacts. Inserting the battery into the case and clicking the switch, you can achieve a bright directional glow of the lamp. Having done these actions, we have formed just what is called the electrical circuit (in professional slang - assembled circuit). The current source of electricity (batteries) rushed along the path: contact of the positive pole - conductor, tumbler - lamp - negative pole. This is called the "simplest electrical circuit". In the example with the flashlight, there are three elements: the source of the EMF, the toggle switch and the lamp. It is worth noting that the movement of electrons (current) is possible only in a closed loop, so if the toggle switch is disconnected and the circuit is broken, it will disappear, although the source voltage remains. By the way, all processes can be described and calculated not only through the current, but also by means of voltage, power, EMF.
A universal calculation tool is Ohm's law. In this case it looks like:
I = E / (R + r),
where I is the current, Ampere; E - EMF, Volts; R -resistance of the lamp, Ohm; r is the resistance of the EMF source, Ohm. In the example used, the effect of the resistance of the conductor and toggle switch is not taken into account, since it is negligible.
So, the electrical circuit and its elements caninclude a power supply, resistors, capacitors, inductors, semiconductor components, etc. And all this must be connected together by conductors forming a continuous path for the passage of current.
Simple chains are divided into unramified andbranched out. In the first case, the same current passes through all the constituent elements (the rule for the serial connection of consumers). In the second case, one or more branches connected with the simplest contour under consideration by means of nodes are additionally added. In this case, a mixed connection of chain elements is formed, so the value of the current flowing in each branch is different. Here the branch is a part of the electrical circuit, on all elements of which flows the same current, and opposite ends of which are connected in two nodes. Accordingly, a node is a point of an electrical circuit in which three or more branches converge. In principle circuits nodes are often just points, which simplifies perception (reading).
