# Logic Gates and Boolean Algebra

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Boolean Variable - Have 2 Discrete values - true and False

• False is Usually - 0
• True is Usually - 1

OR Function : The output is true if either or both inputs are true.

• If both gates are open the output is false
• whereas for example if A is open and B is closed the value is still true
• another way of representation the information is through Boolean Equation.
• Eg: A(closed) + B(closed) = Q(Output = true)
• A = A gate
• + = Is not a plus sign but AN OR SIGN
• B= A gate
• Q = Output(Could be a lamp)
• So it could be written as A+(or) B = Q
• You can also draw a truth table another way of representing it
• OR Gate Symbol

And Function - the output is true only if all the input are true

• This gives output to be true only if all the situations are met for instance
• Lamp on if :supply is on= true AND door open = true, only then will the light turn on .
• Where as it would not work if : Supply is on = True And Door is open = False : in this case the light will not turn on because the conditions have not been met
• Lets take…