Logic gate (electronics) || logic gate formula || basic concept of gate

Exam preparations August 27, 2019 0

LOGIC GATE (ELECTRONICS)

We know that that a digital circuit works on two voltage level : 0 and 1.0 and 1 find linkage to the binary number system , There are two symbols or positive values , 0 and 1 . These two number are represent all the number quantity using binary number.

The basic building block of digital circuit is a logic gate .The logic gate enter two or more input signals for designed and produced one output signals .The terminal of logic gate are two conditions 0(for low) & 1 (For high)

The basic gate are AND , OR, & NOT gate where the complex gate are NAND , NOR , & XOR gate & XNOR gate. And NAND gate and NOR gate are called universal gate.

AND gate:

The function of AND gate is identical .AND gates takes two or more signal and return only one signal . AND gate is called logic multiplication.
truth table :

AND gate for 2-input

The boolean expression for the 2-input gate is F = A . B
for the 3-input gates is F= A . B . C

AND gate for 2-input

OR gate:

The function of OR gate is identical.OR gates takes two or more signal as input and give output only one output. OR gate is called logic addition.

Truth table:

OR gate for 2-input

The Boolean expression for the 2-input gate is F = A + B
for the 3-input gate is F= A + B + C

OR gate for 2-input

NOT gate:

The function of NOT gate is identical to that of NOT gate operator. The NOT gate circuit inverts the logic sense of binary signals .so therefor called Inverters.
Truth table:

NOT gate for 2-input

The Boolean expression for the 2-inputs gate is F = A'

NOT gate for 2-input

NAND gate:

This gate is combination of AND and NOT gates. So it is a complex gate. The graphically combination of NAND gate is AND gate symbol.
Truth table:

NAND gate for 2-input

The Boolean expression for 2-input gate is F = (A.B)'

NAND gate for 2-input

NOR gate:

The gate of function is combination of the OR and NOT gate . The graphically symbol of NOR gate symbol with bubble .NOR gate is also reffered to as inverted OR gate.
Truth table:

NOR gate for 2-input

The Boolean expression for 2-inputs gate is F = (A + B)'
for 3-inputs gate is F= (A + B + C)'

NOR gate for 2-input

XOR gate:

The XOR gate stand for exclusive OR gate. XOR gate are use for two way commonly use in our homes for staircase light .
Truth table: