Combinational Logic Flashcards
1
Q
How do represent a negative/positive number in binary?
A
NEGATIVE - Add an MSB and make it 1
POSITIVE - MSB should be 0
2
Q
What does a XOR gate do?
A
The gate produces a HIGH when the two outputs are opposite
3
Q
How does a half adder circuit work
A
The XOR gate acts as the sum and the AND gate acts as the carry
4
Q
How does a full-adder work
A
Has the ability to perform the addition of 3 bits
5
Q
A + A’B =
A
A + B
6
Q
A + AB =
A
A
7
Q
(A+B)(A+C) =
A
A + BC
8
Q
Define a multiplexer and its function
A
-Drives several inputs to one output
-Uses selector inputs to select data
9
Q
Define an encoder and its function
A
Reduces the number of outputs from several inputs
10
Q
Describe how a Decimal to BCD encoder works
A
-The encoder has 10 inputs (1 for each decimal digit) and 4 outputs for the BCD
