## Tuesday, November 25, 2014

### Logic Gates and Truth Tables of Universal Gates

A logic gate  is a particular electronic circuit to execute a certain logic that we are interested.The kind of logic that you want to execute depends on the requirement.

For example assure that you’re having a fan that has to be switched on.Let it has two switches available at the two sides of a room.If you want the fan to be switched on when at least one of that switches is on, the kind of the logic that you shall execute is similar to OR gate logic.

And if you would like to have your fan to be switch on only when both the switches are on, then the kind of the logic that you want to execute is called and the gate logic. Whenever the switches on if you want the fan to be switched off and vice versa, then the kind of the logic that you are looking for is actually a NOT gate.All this logic gates works basing an algebra called Boolean algebra.

OR gate works basing on the union logic,AND gate basing on intersection logic and NOT  gate basing on negation logic of mathematics.

OR gate

This works basing on the union function of the mathematics. You might know that if there are two functions and we will write the member in the union function when it exists at least in any one of the functions.

AND  GATE

This works basing on intersection function of the mathematics.The output will be on when only both the inputs are on in this kind of the gate. The NOT gate just reverse the input that is given and make it as the output.

NOT gate

NOT gate is a negation gate. Whatever the input that is given,IT will be just reverse that INPUT. That means if the input is ON, the output will be OFF and vice versa.

This three gates are called BASIC gates which are going to be useful to execute basic logic that we wish to execute in any electronic circuit. Anyway there are further hybrid gates available in the logic gates called  NOR and NAND Gates.

NOR gate

NOR gate is the combination of OR  gate and  NOT gate. The results of this gate is the negation results of the OR  gate. The truth table of the gate is shown below. This gate is also called as a universal gate because we can get all the basic gates with this gate.

NAND GATE

NAND gate is a combination of NOT  gate and AND  gate. The output of this gate is reciprocal of the AND gate. This gate is also called as a universal gate. The truth table of the gate is shown below.

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