1. Electronic circuits as perceived by a beginner

In my case, electronic circuits feel complicated and are really difficult to approach.
While preparing and writing the previous lectures, I saw many examples of electronic circuits being compared to the movement of water.
You can think of a circuit as the process of creating a channel through which electrons (free electrons) can move.
Couldn't we call the process of arranging devices along the paths along which electrons move to perform various roles circuit design?
We set up devices here and there that perform various functions, such as widening or narrowing the waterway, installing gates, creating branching waterways to send water in different directions, and waiting in tanks.
Let's learn more through a simple circuit.

2. Super simple circuit
Figure 1-1 is the actual shape, and 1-2 is a circuit diagram showing the same circuit symbolically.
Please familiarize yourself with the symbols for each element as they will not be explained separately in the lecture.
In [Circuit Diagram 1], the path that electrons travel is a single path.
The current has nowhere else to go, and it goes from the + pole of the battery to the - pole, passing through the resistor and the LED.
Resistance limits the current by narrowing the path.
LED is also a type of diode, a device in which electrons and holes are converted into light.
It is a simple circuit, but it can do the job of generating light.

2. Super simple+ circuit

[Circuit diagram 1] is a circuit that generates light until the batteries are completely consumed.
But if you want to make a circuit that can be turned on and off only when needed, you can add a switch.
[Circuit diagram 2] is a circuit with a switch added.
Adding a switch allows you to cut off the current.
Switches have now created circuits that can do more.
Now it can be used as a signaling device that can send signals like Morse code. ^^
It's a bit more complex circuit.
2. Super simple++ circuit
Now, if you want to send more signals, you can just add LEDs.
It's time for parallel circuits. The circuits above are circuits where components (also called elements) are connected in series.
If you connect LEDs in series, they will all turn off at once when you turn off the switch (because they are single-ended).
So this time we add a path. One LED and one switch were added.
It looks a bit complicated. Now we can create more complex signals using two LEDs.
The current passes through the resistor, meets the fork in the path, is divided, and creates light as it passes through LED1 and LED2, and then passes through the switch and recombines.
You can now control the LEDs individually with Switch 1 and Switch 2.
So to speak, it became possible to express 2 bits.
In the end, wouldn't it be fair to say that even complex electronic circuits are made up of a combination of simple functions?
In the next lecture, we will learn about the famous Ohm's law and Kirchhoff's laws through simple circuit experiments.