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BOOLEAN
Logic gates
are an important building block of a digital circuit, which are
employed in all of our modern computers. The microchips of computers are arranged in thousands of logical gates, which
make precise and consistently reliable conclusions. There are no limits in the amount of gates that can be used and
with the advancement of microchip technology; we can constantly add more gates to newer chips. There are eight main
logic gates, which can be divided into two main subgroups: non-inverted and inverted which gives the exact opposite
answer of the non-inverted. There are four logic gates in each subgroup and as mentioned before, eight basic logic
gates and with these many complex operations can be performed. These eight gates are (put links on each word) Buffer,
AND, OR, EOR, NOT, NAND, NOR, ENOR. Six of these eight logic gates contain two inputs and all the basic logic gates
contain one output. All logic gates have two conditions that are represented by binary numbers and different voltages.
The binary number zero and a voltage of zero represent the off or low switch and the binary number one and a voltage
of five represent the on or high switch. Theses gates allow the computer to do things such as add, divide, multiply,
do simple yes and no reasoning in certain situations along with other things.
Non-inverted Logic Gates
Buffer - The most basic logic gate contains one input and output, where your input will equal your output, in any situation. ***(I will draw simple pictures of gates for web page)
AND - This gate contains two inputs and a single output. It requires both inputs to be in the on position for
the output to be on; otherwise the output will be off.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
0 |
| 1 |
0 |
0 |
| 0 |
1 |
0 |
| 1 |
1 |
1 |
OR - The OR gate is similar to the and except for the fact that it only needs one of the two input gates to be on
for the output to be on.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
0 |
| 1 |
0 |
1 |
| 0 |
1 |
1 |
| 1 |
1 |
1 |
EOR (Exclusive OR) - Like its name the EOR, also known as XOR is similar to the OR gate. The difference between them
is that the output is false if both inputs are true or false.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
0 |
| 1 |
0 |
1 |
| 0 |
1 |
1 |
| 1 |
1 |
0 |
Inverted Logic Gates
NOT - Another simple gate with only one input and output. This gate takes the input, and inverts it giving a
reversed output.
| Input 1 |
Input 2 |
Output |
| 1 |
0 |
| 0 |
1 |
NAND - This gate is an AND gate which is followed by a NOT gate, inverting all the outputs.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
1 |
| 1 |
0 |
1 |
| 0 |
1 |
1 |
| 1 |
1 |
0 |
NOR - It follows the same priciples as the NAND gate. It is a OR gate followed by NOT giving an inverted output.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
0 |
| 1 |
0 |
0 |
| 0 |
1 |
0 |
| 1 |
1 |
1 |
ENOR (XNOR) - Like the NOR and NAND this is a EOR followed by a NOT giving inverted outputs.
| Input 1 |
Input 2 |
Output |
| 0 |
0 |
1 |
| 1 |
0 |
0 |
| 0 |
1 |
0 |
| 1 |
1 |
1 |
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