Easy Peasy Logic Gates, Part 2Continuing our guide to understanding basic logic gatesImeshaBlockedUnblockFollowFollowingMay 28Photo by Chris Reid on UnsplashThis is my second article on logic gates.
If you haven’t read the first, here it is.
In the previous article we discussed the basic AND, OR and NOT logic gates.
Now we are going to learn 4 different logic gates, which are derivations of basic logic gates.
NANDNORXORXNORNow we will discuss each gate’s basic function, standard symbol and its truth table separately.
NAND GateA NAND gate has two inputs and a single output.
It is made from connecting the NOT gate to the output signal of the AND gate.
In this logic gate, the output signal is low only if the two gate input signals are high — otherwise, the output is high.
Because of this, we can say that the operation of the NAND gate is the inverted signal of the AND gate.
The derivation of this logic gate can be shown in the following image.
Derivation of NAND Gate using AND gate and NOT gateHence, the standard NAND logic gate symbol can be expressed like this:Standard NAND Gate SymbolAccording to the diagram, the A and B denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for NAND gateNOR GateBeing similar to NAND gate, NOR gate also has two inputs and a single output.
It is made from connecting the NOT gate to the output signal of the OR gate.
In this logic gate, if either input signal is high, the output will be low.
Because of this, we can clearly say that the operation of the NOR gate is the inverted signal of the OR gate.
So the derivation of this logic gate can be simply shown like this:Derivation of NOR Gate using OR gate and NOT gateHence, the standard NOR logic gate symbol can be expressed like this:Standard NOR Gate SymbolAccording to the diagram, the A and B denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for NOR gateXOR GateXOR is actually an abbreviated name for exclusive OR.
This logic gate also has two inputs and a single output.
In this logic gate, if both input signals are high or low, the output will be low.
If the logic gate has more than 2 inputs and a single output, an odd number of high inputs result in a high output.
The standard XOR logic gate symbol can be expressed like this:Standard XOR Gate SymbolAccording to the diagram, the A and B denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for XOR gateIf the XOR has 3 inputs, it is drawn like this:XOR Gate symbol with 3 inputsA, B and C denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for XOR gate with 3 inputsXNOR GateXNOR Gate is the invert of the exclusive OR gate.
Similar to XOR, this logic gate also has two inputs and a single output.
In this logic gate, if both input signals are high or low, the output will be high.
If the logic gate has more than 2 inputs and a single output, an odd number of high inputs result in low output.
The derivation of this logic gate can be simply shown in the following image.
Derivation of NOR Gate using OR gate and NOT gateSo, the standard XNOR logic gate symbol can be expressed like this:Standard XOR Gate SymbolAccording to the diagram, the A and B denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for XNOR gateIf the XNOR has 3 inputs, it is drawn like this:XNOR Gate symbol with 3 inputsA, B and C denote the input signals where Z is the output signal.
Therefore, the truth table can be written as follows:The truth table for XNOR gate with 3 inputsThis concludes the series of introduction for basic logic gates.
I hope you guys enjoyed learning about the behaviour of basic logic gates!.. More details