What is electronics?

Electronics is the study of the control and the flow of electrons. To understand what that means we first need to know what an electron is.

Electrons

An electron is a type of electric charge. An electric charge is a basic property of matter carried by some subatomic particles, that governs how the particles are affected by an electric or magnetic field. They can be negative and positive. Two objects that have an excess of one type of charge exert a force of repulsion on each other when relatively close together. Contrarily when one object is positively charged and the other negatively charged, both objects attract each other when relatively near. Electric charges are measured in coulombs.

An electron is a one of those electrical charges that is negatively charged. They are the opposite of the protons, which are positively charged. The charge of an electron is $1.60217662 \cdot 10^{-19} coulombs$.

So what is electronics?

Now that we know what an electron is, we can elaborate a bit more on what electronics is. As we said earlier, electronics is the study of the control of electrons. By controlling electrons we can do a lot of things like computing complex calculations very fast, tell a machine to move or do a certain action, etc.

The way we control electrons is by making them flow through an electric circuit. Electric circuits are a bunch of wires, which the electrons flow through, set up in a specific way to get the desired behavior. These wires are connected to several electric components that allow us to play with the electrons, like a transistor which acts kind of like a light switch. A computer is an example of a very complex electric circuit.

So in short electronics is the study of moving negatively charged particles called electrons, through an electric circuit to do a specific function like complex calculations or controlling machines.

How are electrons moved around?

Ok, great, but how are electrons moved? As we mentioned earlier electrons are negatively charged and protons are positively charged. Since these two particles are opposite, they attract each other. This means that we can put a proton on one side and an electron on the other and they will try to get together, just like a magnet. So electrons move from one place to another pulled by the protons.

This is called electrical tension, voltage or potential difference. That is negatively charged objects (electrons) being pulled toward higher voltages, while positively charged objects (protons) being pulled towards lower voltages.

Electrical current

Electrical current is the flow of electric charges. The amount of electrical current going through a specific point is called Intensity $ (I) $ and it is measured in amperes

$$ amperes = \frac{coulombs}{second} $$

If n charges q go through a specific point, the total charge $ Q $ will be: $$ Q = n \cdot q $$

And since intensity is the amount of electrical charges going through that specific point over a specific amount of time $ t $, we have that intensity is:

$$ I = \frac{Q}{t} = \frac{n \cdot q}{t} $$

We can classify materials depending on their conductivity of electrical current:

  • Insulators: The electric charges (usually electrons) can’t move through them.

    Example -> Glass

  • Conductors: The electric charges can move freely through them.

    Example -> Metals

  • Semiconductors: It’s an intermidiate between the previous two types.

    Example -> Silicon

Per convention the direction of electrical current is the one of the positive charges. So if we have a flow of electrons, the direction of the current is opposite to the movement of the charges.

  • When current doesn’t change it direction, we call it direct current.
  • When current does change its direction, we call it alternating current.