Adders & Comparators Flashcards
What is a Half Adder
Adds 2 Bits Together, 2 Inputs Generate a Sum and a Carry.
No Input Carry
Draw a Truth Table for a Half Adder
Write the SOP for the Sun and carry Outputs
Draw the Logic CIrcuit
What is a Full Adder
Adss 3 Bits Together, 2 Inputs and a Cary input generate 2 Sum and a Carry Output
Draw a Truth Table for a Full Adder
Write the SOP for the Sun and carry Outputs
Draw the Logic CIrcuit
Draw a Block Diagram for an Adder that Adds two 4-bit Numbers Together
If we wanted to Make an 8-bit Adder, what would you do?
Explain why a full adder is mostly used for the final 2 bits, instead of a half adder.
Get two 4-bit adders, put the carry output of one 4-bit adder, and put it as carry input to another
What is a Compliment
For a specific calculation ie. 64-38
A Compliment is a number that when added to the first number (64) produces an answer where the MSB is 1, yet the proceeding digits are the answer to the calculation.
The Compliment for the Calculation 64-38 is 62
64-38 = 26
64 + 62 = 126
Show how Two’s Complement works
How do you Check your answer is correct, if it is in Two’s Compliment (Negative) form
Invert all digits
Add 1
The answer given is now Positive
Calculate -15-7 (base 10) via Two’s Compliment
Calculate 9-11 via Two’s Compliment
What is the Function of an Equality Comparator
Write the SOP Expression for a 4 Bit Equality Comparator
Draw the Logic Circuit
Outputs 1 if two N-Bit Numbers are equal, 0 otherwise
What is the Function of a Magnitude Comparator
Write the SOP Expression for the 3 Required Functions
Draw the Block Diagram
Out puts whether two N-Bit numbers are A=B , A>B , A<B
