Logic Gates and Adders Flashcards
What are gates?
a device that performs a basic operation on electrical signals
What are gates made of?
transistors
What are circuits?
Gates combined to perform more complicated tasks
What are Boolean expressions?
uses Boolean algebra, a mathematical notation for expressing two-valued logic
What are logic diagrams?
a graphical representation of a circuit; each gate has its own symbol
What are truth tables?
a table showing all possible input values and the associated output values
What is functional notation?
uses a function name followed by a list of arguments in place of the operands used in a boolean expression
What are the 2 main roles of a transistor?
- Amplifier
- Binary Switch
What are the 6 types of gates?
- NOT
- AND
- OR
- XOR
- NAND
- NOR
How many one-input operations do we consider?
4
How many two-input operations do we consider?
16
How do NOT gates work?
Takes 1 input (0,1)
Output: will be the opposite of the input
How do AND gates work?
Takes 2 inputs
Output: if both inputs are 1, then 1, if not then 0
How do OR gates work?
Takes 2 inputs
Output: if both are 0, output is 0, if not, then 1
How do NAND gates work?
Takes 2 inputs
Output: if both are 1, then 0; otherwise, output is 1
*exactly like the outputs of AND, but then the opposite
How do NOR gates work?
Takes 2 inputs
Output: if both are 0, then 1, otherwise 0
*exactly like the outputs of OR, but then the opposite
How do XOR gates work?
Takes 2 inputs
Outputs: if both inputs are the same, then 0; otherwise, 1
What is a half adder?
a circuit that computes the sum of two bits and produces the correct carry bit
What is a full adder?
a circuit that computes the sum of two bits and a carry bit and produces the correct carry bit
