數位邏輯-基本邏輯閘

Digital logic – Basic logic gates

Symbol：

INPUT OUTPUT 　A 　　F 　0 　　1 　1 　　0

Bollinger Algebra ： f=A ̅　or　f=A’

OR Gate：

A HIGH output results if one or both the inputs to the gate are HIGH.

Symbol：

INPUT OUTPUT A B F 0 0 0 0 1 1 1 0 1 1 1 1

Bollinger Algebra ： f=A+B

Encoder： C=A4+A5+A6+A7 B=A2+A3+A6+A7 A=A1+A3+A5+A7

Expand to 3 inputs.

AND Gate：

A HIGH output results only if all the inputs to the AND gate are HIGH.

Symbol：

INPUT OUTPUT A B F 0 0 0 0 1 0 1 0 0 1 1 1

Bollinger Algebra ： f=AB

Data transfer and erase.

2 to 4 decoder.

Expand to 3 inputs.

NOR Gate：

A HIGH output results if both the inputs to the gate are LOW.

Symbol：

INPUT OUTPUT A B F 0 0 1 0 1 0 1 0 0 1 1 0

Bollinger Algebra ： f=f ̅=(A+B) ̅

Replace NOT with NOR.

Replace AND with NOR.

Expand to 3 inputs.

NAND Gate：

A LOW output results only if all the inputs to the gate are HIGH.

Symbol：

INPUT OUTPUT A B F 0 0 1 0 1 1 1 0 1 1 1 0

Bollinger Algebra ： f=(AB) ̅

Replace NOT with NAND.

Replace OR with NAND.

Expand to 3 inputs.

XOR Gate：

A true output results if one, and only one, of the inputs to the gate is true.

Symbol：

INPUT OUTPUT A B F 0 0 0 0 1 1 1 0 1 1 1 0

Bollinger Algebra ： f=A⊕B =A ̅B+AB ̅ =(A ̅+B ̅ )(A+B)

X=0 Buffered output X=1 Inverted output

Expand to 3 inputs.

XNOR Gate：

A high output results if both of the inputs to the gate are the same.

Symbol：

INPUT OUTPUT A B F 0 0 1 0 1 0 1 0 0 1 1 1

Bollinger Algebra ： f=(A⊕B) ̅ =A⊙B =(AB) ̅+AB =(A ̅+B)(A+B ̅ )

X=0 Inverted output X=1 Buffered output