''TRANSISTOR''

 

                                             First coumputer ENIAC by vacume tubes(18,00).
 


The history of Transistors very diificult,before the invention of transistors we use vacume tubes but ''vacume tubes''are are made up of glass so it brokes easily and consume high power and it smash at limited time period so it is so expensive and also not easy to use and the main thing is vacume tubes are so huge.The efficiency of the vacumetube transisor is very low that means 1%..



First IC invented by intel in 1971 with 2,300 transistros,now in IC billions of transistors are present.
       Did you know  electronics is nothing but transistor. We know that'' the first coumputer ''ENIAC'' is very huge it takes a big room to settle so it is not possible to use freely. in first ENIAC coumputer 18,000 vacume tubes are used but thier efficiency is very less.But luckly brilliant scientists '' JOHN BARDEEN, WALTER BRATTAIN & WILLIAM SHOCKLEY ''invented Transistor in the year of 1948'' it is greatest,wonderful,awesome invention 20th century'' the transistor is made up of ''Silicon & Berelium metal '' and the main thing is silicon comes from sand when sand is heated very very high temparature it gives silicon atoms,so the cost of transistor is cheap and easy to use.

 
 
The efficiency or power of the first computer is 1% but the computer made with transistor is 200%. and also the main thing is the'' IC(integrated circuit) is maximum made up of transistor'' only and other is resistors,capacitors........are  there.


Let us know about the transistor connections and working and also transistor as an amplifier.....
  
Tansisor is same like human body like nerves in brain,nerves amplify signal same like transisitor,transistor is backbone of electronics.
Transistors are so many types and so many available.
The most important&popular transistor is BJT(Bipolar junction transistors)

TRANSISTOR=TRANSFER+RESIST
transfer=transfer current.
Resistor=resist current.

There are two types in BJT tansistors.

             -------------------》NPN
BJT
             -------------------》PNP

NPN & PNP has commonly has  COLLECTOR , BASE , EMMITTER .

 

Collecter is large in size & moderately doped.

Emmitter is moderately size & strongly doped.

Base is small in size & weekly doped.
Note:- moderate-middle.
The main thing is in transistor ''electrons always flows from
N ----》P  direction only (north to south)'' if the transistor flows from N----》P direction it is forward bias&input current that means input gives to n---》p only .

If the electrons flows from N《----P is on reverse direction is called reverse bias and output current is taken from this 《---- P only.
 In the figure N --》P is forward and N《---- p is reverse bias.



    It is NPN,arrow(>)is in left side so it is Emmitter
The circuit diagram of transistor is simple with some logic.
Transistor has three parts those are base,emitter&collector.
First base is very simple with simbol ''T'' above the t two lines on each size those are emitter and collector,to identify these a small arrow(>) is placed on one side that is emitter and other is collector.
The other main thing is ''how to identify NPN or PNP ? ,small trick we use that is,we know that Electric current always flows from Positive(+) to Negative(-) we see in figure arrow position is identify



So this is all about transistor drawing.
Transistor Connections:-
There are three types of connections or configurations are there,those are seen by drawing.

                                           


                                this is common base transistor,it is not used for amplifier.

  
 
this is common collector configuration,this is also not important to amplifier.
 


This is common emitter configuration l.This is only used for Amplifier.Because emitter is highly doped.
AMPLIFIER connection & working : for making amplifier common emitter configuration(both base and collector is commonly connected to Emitter ) is used.weak signal or power is given to the Base and Emitter as input with th middle help of capacitor and resistor And output is taken to collector and emitter and middle is also capacitor and resistor is connected and Earth is taken at emitter.then the amplifier week signal to strong signal by making high amplitude.you may understand by using this picture.

Source: jan visual physics (youtube).
Reference:tutirials point india ltd.(physics)
   Telugu badi(youtube)make of chip.

Thank you......

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