NOT gate

                       Hello students once again welcome back.In last post we have learned about AND gate. In this post we will learn about NOT gate. 

NOT gate has only one input and ouput. Output is not input .ie. Output is compliment of input . For example , when input is high(1) , output is low(0) and vice versa. IC 7406 is hex inverter. NOT gate is also called as Inverter. In Boolean Algebra over bar (-) indicates NOT gate. Symbol of NOT gate and truth table is shown below:-

 This is about NOT gate . In next post we will learn about OR gate.

AND gate

                   Hey student's once again welcome to all of you. In last topic we have seen the introduction to Logic gates , necessary of Logic gates. In this topic I am going to tell about AND gate . Let's begin!!
                   AND gate has one or more inputs but only one output.Output is high when all inputs to AND gates are high (1). So , we can define AND gate as the gate whose output is high only when all inputs are high. Trick to remember when the Output of AND gate is high is that AND gate  is same as conjunction in maths . In maths truth value of sentence is true when all given statements have truth value True. Just like in AND gate output is high when all inputs are High.
                           When gate has n inputs it is called n bit AND gate. In Boolean Algebra '.' represent AND gate. IC 7408 is quad dual input AND gate . The symbol and truth table of 2 input AND gate is as follows:- 

                                             
                                                                                          OUTPUT EXPRESSION IS Y= A.B (Read as A and B). 
                          In next post I will tell you about NOT gate.

Introduction to Logic Gates

                     Hello student's I hope you have started studying 12th HSC electronics. Some of you might have read some lessons. I will tell you about logic gates in easy way.
                     For a time being consider gate as our lock which we use in our day to day life. When does it open? Obviously when we put key of that lock . Here key is our input and lock is out put . Similarly in logic gates we give some inputs to get some output .
                    Now question arises why we need logic gates? Answer is in computer there are several components. By using this components we can get 10 different states but this states are not well defined but 2 well defined states can be obtain from these components, so we use Boolean Algebra i.e. two states Algebra. Logic Gate uses Boolean Algebra. In computer and microprocessors logic gates are used for various purposes for example counting , addition,substraction,multiplication,divison,etc.
                    Logic Gate is device which has one or more inputs but only one output. Output is high when input word is recognized by gate just like when we put proper key of lock it open i.e. it opens , output is low when input is not recognized by gate just like when we put wrong key in lock it doesn't open. In logic gate output high is denoted by 1 and low output is denoted by 0
                   There are two types of Logic :- 1) Positive Logic and 2) Negative Logic
                  In positive logic input 1 is shown by more positive of two voltage levels and 0 by other voltage level. For example if input voltages are 0 and 5 then 1 is represented by 5 and 0 is represented by 0 . If inputs voltages are -5 and 0 then 1 is represented by 0 and 0 is represented by -5.
                In negative logic 1 is represented more negative of two voltage levels and 0 is represented by other voltage. For example if voltages are 0 and 5 then 1 is represented by 0and 0 is represented by 5. If two voltage levels are 0 and -5 then 1 is represented by -5 and 0 is represented by 0
               There are 3 fundamental logic gates :-1) AND gate 2) NOT gate 3) OR gate .
               We will see in details of these 3 gates in my next blog. Thanks for reading!!