I hope you have read the basic things about electronics or Click here....
Now lets see some basic electronic components and its uses........
Now lets see how to find the value of a resistor.
A Transistor is an electronic semiconductor device which is used to amplify and switch electronic signals and electrical power. It has at least 3 terminals for connection to an external circuit.
A transistor in which a thin P type semiconductor is placed in between two N type semiconductor is called a NPN transistor and a transistor in which a thin N type semiconductor is placed in between two P type semiconductor is called a PNP transistor.
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits and components such as transistors, resistors, capacitors etc. on one small plate ("chip") of semiconductor material, normally silicon. This can be made much smaller than a discrete circuit made from independent electronic components.
Now lets see some basic electronic components and its uses........
Resistors
 |
| Resistors |
In simple words, resistors are the devices which resists or
blocks the flow of current. In other words resistors are used to control the
flow of current in a circuit. Generally the resistors are made of materials
such as carbon film, Chromium, nickel etc. The resistance in an electronic
circuit is measured in ohms and is denoted by the Greek word omega (Ω). the
current and voltage in a circuit is varied according to the value of
resistance. As the value of resistance increases, the voltage and current
decreases.
The value of a resistor can be easily find out. There will
be 3 or more color bands on a resistor.
Each color band represents each value. This is the color
code of the resistor.
We can see 3 color bands placed near by and one away from
them. Generally this fourth band will gold or silver in color. Now hold the
resistor in such a way that the 4th band comes to the right side.
Now count the colors
from left to right as 1,2,3,4 etc. now see the table for the color values. Now
all you have to do is that combine the first 2 color values together and
multiply that value with the multiplier corresponding to the 3rd
color band.
The 4th band denotes the tolerance of the resistor.
Tolerance is the variation in the resistance value of a resistor when connected
to a circuit.
The wattage of a resistor can be identified from its size.
As the size of the resistor increases, the power also increases. The resistors
are available in 1/4W, 1/2W, 1W, 2W, 5W, 10W etc.
 |
| Resistor color code table |
For example :
a resistor has color bands as follows
Green, Blue, Brown and Gold
from the table, the value of Green is 5, Blue is 6, Brown is
10 and Gold is 5%.
Now combine the first 2 color codes. ( Combine Green and Blue
→ 56 ).
Now multiply this value with the multiplier corresponding to
the 3rd band.( Multiplier of Brown is 10 Ω ).
56 X 10 Ω = 560 Ω
Example 2 :
Yellow, Violet, Orange and Silver
Combine the first two codes ( Yellow & Violet → 47 )
Multiply 47 with the
multiplier of Orange (1K Ω).
47
X 1K Ω = 47 K Ω
NoTe :
1K Ω = 1000 Ω
1M Ω = 1000k Ω
Capacitors
 |
| Capacitors |
Capacitor is an electronic component which is used to store
electric charge. The capacitor is also used as a filter in some electronic
devices. The capacitors are made up of insulators such as paper, Mica, Ceramic
etc which are placed in between two Metallic plates ( Electrodes ). The
insulator placed in between the electrodes are called dielectric. A capacitor
blocks Direct Current ( DC) and passes
Alternating Current ( AC ). There are three types of capacitors. They are....
·
Electrolytic Capacitor
· Ceramic Capacitors
· Variable Capacitors
The ability of a capacitor to store Electric Charge is
called Capacitance. It is measured in Farad. The farad is a larger value. So in
practical, we use Pico Farad (PF), Nano Farad ( NF )
or Micro Farad ( µf ).
1
Farad = 1000000 µf
1 µf = 1000 nf
1
nf = 1000 pf
 |
| Capacitor Codes and values |
Please click here to find the capacitor values.
Diode
 |
| Diodes |
Diode is an electronic component which which allows the
current to flow only in one direction. The
diode is a semiconductor device. It allows the current to pass through
it when forward biased and acts as an insulator when reverse biased . When
forward biased, the barrier at the PN junction gets destroyed and the current
flows through the diode and when reverse biased, the barrier at the PN junction gets stronger and acts as an
insulator. This is happened due to the repulsion of same charges or the
attraction of opposite charges.
Identification of terminals
:
Hold the diode in your hand and look for a band on the
diode.
The terminal near the diode is Negative ( -ve ) and the
terminal which is away from the band is Positive ( +ve ).
Transistors
 |
| Transistors |
A Transistor is an electronic semiconductor device which is used to amplify and switch electronic signals and electrical power. It has at least 3 terminals for connection to an external circuit.
There are two types of transistors. They are....
·
NPN Transistors
·
PNP Transistors
A transistor in which a thin P type semiconductor is placed in between two N type semiconductor is called a NPN transistor and a transistor in which a thin N type semiconductor is placed in between two P type semiconductor is called a PNP transistor.
Transistor as a switch
Consider an NPN transistor...........
When a Positive( +ve
) voltage is applied to the base of a NPN transistor, there will be a flow of
current between the Collector and Emitter of the transistor. In other words,
the transistor goes to on state when a +ve voltage is applied at the base and
it goes to off state when -ve voltage is applied to the base.
IC CHIPS ( Integrated Circuit Chips )
 |
| IC chips |
Inductors
 |
| Inductors |
An inductor is nothing but a coil. It is as same as a capacitor but opposite in nature and properties. It blocks AC ( Alternating Current ) and passes DC ( Direct Current ). A capacitor stores energy in Electrical field on the other hand an inductor stores energy in magnetic field.
Since an inductor blocks AC signals it can be used as a filter.
Transformers
 |
| Transformer |
A transformer is an electrical device which is used to increase or decrease the alternating current. A transformer has two coils ( Primary and Secondary ). The principle of a transformer is Faraday's law of Electromagnetic Induction. The input signal is given to the primary coil of the transformer. It induces an e.m.f or voltage on the secondary coil. Hence we can find an output voltage without having any changes in the freequency.
There are two types of Transformers. They are.....
- Step Up Transformers
- Step Down Transformers
Step Up Transformer
A step up transformer is used to produce a voltage higher than the input voltage. In a Step Up Transformer, the secondary winding is greater than the primary winding.
Step Down Transformer
A Step Down Transformer is used to produce a voltage lower than the input voltage. In a Step Down Transformer, the secondary winding is lower than the primary winding.
Generally, the transformer used in electronic circuits are Step Down Transformers.
