Electronics for beginners
Lesson 1
In this lesson I am going to introduce the
main electronics components and also
their schematic representation.
Further details about these components will be studied in other lessons
of this course
The schematic diagram is a full map of the electronic equipment. That's why
it's so important to know how to read it.
Below you can see a piece of a PCB
The schematic diagram is the representation of a PCB
A schematic diagram may seem complex at first sight, but in this course we
will make a step-by-step introduction, so that, at the end of this course, it will
seem very simple
Below you can see a piece of schematic diagram
In this first lesson I am going to introduce some symbols of electronic components
which when joined, builds to whole schematic.
Resistors
Below you can see the schematic representation of a resistor
There are two symbols of resistors
Resistors physical formats
There are several resistors formats
Most low power resistors contain rings
Below you can see several types of low power resistors, as
1W, 2W, 3W etc
Power resistors
Below you can see high power resistors as 5W, 7W, 10W, 20W, etc...
Capacitors
There are several types of capacitors
Electrolytic capacitor
Capacitor schematic symbol
Below you can see its physical picture
There are also the ceramic capacitors and other non-electrolytic
capacitors
The main types are: Ceramic,
metalized polypropylene and the polyester type
Now let me introduce you some non-electrolytic capacitors
The ceramic
All non-electrolytic capacitor have the same schematic symbol, as
shown
below
Take a look at some non-electrolytic capacitors
Ceramic capacitor
Polyester capacitor
Metalized polypropylene capacitors
About the pictures above, we can say that:
1- All electrolytic capacitors have polarity ( + and -). So when replacing
them you have to make sure that the + and - marks on the capacitor match
the + and - marks on the PCB.
2- All non-electrolytic capacitors have the same symbol in the schematic
diagram
3- All non-electrolytic capacitors have no polarity, and you don't have to
worry about +/- polarity when replacing them
Diodes
Below you can see a diode
Diodes are semiconductors
It means that an electric current flows through in one direction only
The mark on the diode is always the positive side, wich we call cathode
Below there are the main types of diodes
Rectifier diode
It's the most common diode, used on the output of power supplies to
rectify them
Varicap diode
Used in TV tuners. It's a diode which capacitance varies according to
the voltage which is applied on it
Light emiting diode
Known as LED. It's used on several electronic panels to show functions
They are presented on several colors as green, red, yellow and others
Zener diode
It is used to reduce a voltage
For example, a 6.2 volts zener
has the property to reduce a
12V power supply to 6.2V
It is used in several functions as power supply regulator, protection, etc
Transistors
Transistors have many physical
formats but their schematic representation are always the same
It this lesson, we will only show the bipolar transistors. In further lessons
you will see other transistor types
There are only two types of transistor polarities: PNP and NPN
By observing the pictures above, we can see that the base is always on the
center, the arrow is the emitter and the
other one is
the collector.
These
positions are the same regardless of the
transistor polarity
Notice that the base, collector and emitter are always the same, but only in
the schematic diagram.
In the physical format, the position of the pins will vary according to
the type of the transistor
This will be studied in further lessons of this course
Below you can see the physical aspect of some types of transistors
See you in the next lesson
