Armando Caligiuri, electrons in motion
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Welcome to my web page dedicated to electronics and electrical engineering.

 On this page I will try to define in a simple and appropriate way adapt to the neophytes the immense world behind the two subjects mentioned above, it is not an easy task but I will try. Of course it is impossible to condense a vast subject in this small text, but if you are going to deepen or need professional advice, you can contact me through at the Contact page.
At the end of this document you will find links to the in-depth pages dedicated to active and passive electronic components.

                                                                   
                                                                 Electrical engineering

Let's start with the raw material, that is, what we need to make it work, we're talking about electricity.
The classical definition is, "a flow of electrons circulating in a conductor subjected to a difference in electrical potential", the unit of measurement is the Ampere, abbreviated with the capital A, in honor of the French physicist Andrè Marie Ampère who studied it And defined it.
In the definition of the electric current we have introduced another 'primary parameter, the difference of electrical potential D.D.P. Or electrical voltage, or electric motor force F.E.M. That force that creates electrical imbalance in the atoms of a generic conductor,
And therefore the circulation of electrons, which in the attempt to restore equilibrium create the flow above, it is measured
In Volta, abbreviated in Volt and indicated with the capital V, all this in honor of the illustrious Italian scientist Alessandro Volta, who
Performed so many studies and produced the world's first voltage generator (the Volta electric battery), there are two types of electrical voltage, the continuous one which is constant (not variable in time), and the alternating one (varies in value over time and Can have both positive and negative signs).

Defined by the main artifacts of the entire electric world remains to be defined as a third force, we are talking about electrical resistivity, that is, of that force that obstructs the movement of electrons in a generic conductor (the bond between electrons and the nucleus of the atom), it is measured
In Ohm, in honor of the German physicist Georg Ohm who studied it and defined it, it is indicated by the omega Ω symbol.
Electric power is the work done by the current and the voltage to achieve a given purpose and is measured in W.


From the above it is understood that applying an electric voltage (V) to a generic conductor causes an electron flow (A) which is impeded by the intrinsic resistivity to the conductor itself (Ω). This can be said when working with continuous currents, Alternating current there are several other parameters that must necessarily be taken into account, they are the frequency f (how many times a given current in the unit of time (1 second) passes zero, the capacitance reactor Xc the inductive reactance Xl and the phase shift, These, combined with the resistance, create another equivalent magnitude (ie, the combination of all parameters) called impedance and indicated by the uppercase Z. This is a very large and unmanageable chapter here, otherwise the web page would assume gigantic dimensions and would complicate too much things to those who are now approaching the subject.

There are materials that oppose current flow more than others, that is, they have a higher specific resistivity, they are insulators (rubber, glass, pvc, dry wood, plastic, distilled water), otherwise conductive materials exhibit a very specific resistivity Low, and oppose little to the passage of the electric current (copper, gold, silver, aluminum, brass, usually metal materials).
There are also some material materials called semiconductors (germanium and silicon) which have a neutral specific resistivity, they are a base for obtaining the transistors and the integrated circuits that we will see later, by means of a process called "doping".

But how is electricity produced? The simpler generator is the electric battery, which produces a constant voltage voltage and is
Formed by disks of different conductive material overlapping and immersed in an electrolyte, are currently also available rechargeable batteries, to properly call "electric accumulators" which, after a charging process, subsequently return the accumulated energy.
Nickel-cadmium batteries or nickel-manganese refined type are used for small capacities, but for large capacities, lead-acid accumulators are used, each having positive and negative aspects.


Electricity that comes to our homes is of an alternate type, and is produced from renewable sources, that is, that they regenerate in a short time (photovoltaic panels, biomass, hydroelectric, wind power plants) or from non - renewable sources (petroleum, coal,
Methane, nuclear), however, almost everything is obtained by converting an energy that can be solar, nuclear or other in electric energy, or mechanical energy, by means of a machine called alternator, which works according to the principle of electromagnetic induction.
The energy is then distributed as shown in the figure below.


                                     


To sum up the formulas to calculate at least the main parameters exposed before, ie voltage, current and resistance, to do this comes to the aid of the "Ohm Law" which allows to calculate one of the parameters knowing the other two.
By convention the voltage is indicated by V, the current with I and the resistance with R, as we pass the formulas.
Voltage V = R * I Current I = V / R Resistance R = V / I
The value of electric power is instead given by the multiplication of voltage and current, in essence, W = V * I
Clicking on this text you can download an XLS file that I created specifically designed to calculate all the parameters
from the "Ohm Law".

                                                                       
                                                                         Electronics

To clarify what is the electrical current, how it is produced and distributed to our homes, and how to calculate the main parameters, we can devote ourselves to the most refined aspect, that is, to the real electronics, but what is the electronics? It can be defined simply as the science that creates and uses tools, which use the electric current transforming it into "signals" to process other physical quantities.
The electronics are further divided into two major sectors, Analog Electronics and Digital Electronics.
The analog electronics is the one where electrical signals are processed that can have any zero to infinite value at any time.
Instead, digital electronics can be defined as the one where signals are processed whose values ​​can only be two, 0 or off, or 1 or on.
In this page we will discuss the main components used in electronics, both active and passive, passive components are those that use energy but do not perform signal amplification or production or processing, serve as a tool for polarizing them and running them, on the contrary components Active ones are those that can produce, amplify, or process signals.
Both in electrical engineering and in electronics, to understand the operation of a given circuit, it is necessary to have a pattern that can be both electrical and practical. The electrical or theoretical uses normalized symbols to represent the components used and serves to facilitate the understanding of the operation, whereas the practical one represents the circuit design realization.
Here are some symbols used in the diagrams.

On the pages you have available by clicking the links at the end of this document, you can find a wider discussion of the most used active and passive component in electronics.
Of course it is impossible to condense all these concepts in a small space, my only want to be a good guide for those who are looking at this fantastic world, you can still deepen or ask for professional advice by contacting me, so go to the contact page.
These pages will be enriched in the future of projects about the world of moving electrons ready to be realized and which will serve to focus on what is said.
Thanks for visiting my website and following my guide, go back to visit it

 

                                    

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Armando Caligiuri, Electronic senior expert, electronic and I.T. maintainer, I.T. consultant.      e-mail: info@armandocaligiuri.it
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