GET PAID FOR YOUR TECH TUTORIALS / TIPS - click here
Computer
Fundamentals
Glossary
Term
A term is a collection of variables,
e.g. ABCD.
--------------------------------------------------------------------------------
Constant
A constant is a value or quantity which
has a fixed meaning. In conventional
algebra the constants include all integers
and fractions. In Boolean algebra there
are only two possible constants, one
and zero. These two constants are used
to describe true and false, up and down,
go and not go etc.
--------------------------------------------------------------------------------
Variable
A variable is a quantity which changes
by taking on the value of any constant
in the algebraic system. At any one
time the variable has a particular value
of constant. There are only two values
of constants in the system- therefore
a variable can only be zero or one.
Variables are denoted by letters.
--------------------------------------------------------------------------------
Literal
A literal is a variable or its complement
--------------------------------------------------------------------------------
Minterm
Also known as the standard product or
canonic product term. This is a term
such as 
,
etc., where each variable is used once
and once only.
--------------------------------------------------------------------------------
Maxterm
Also known as the standard sum or canonic
sum term. This is a term such as 
,
etc., where each variable is used once
and once only.
--------------------------------------------------------------------------------
Standard
sum of products form
Also known as the minterm canonic form
or canonic sum function. A function
in the form of the " sum "
(OR) of minterms, e.g:
--------------------------------------------------------------------------------
Standard
product of sums form
Also known as the maxterm canonic form
or canonic product function. A function
in the form of the " product "
(AND) of maxterms, e.g:
--------------------------------------------------------------------------------
Sum
of products
Also known as the normal sum function.
A function in the form of the "
sum " of normal product terms,
e.g:
--------------------------------------------------------------------------------
Product
of sums
Also known as the normal product function.
A function in the form of the "
product " of normal sum terms,
e.g:
--------------------------------------------------------------------------------
Normal
(general) sum term
A term such as 
etc.
--------------------------------------------------------------------------------
Normal
(general) product term
A term such as 
etc.
--------------------------------------------------------------------------------
Truth
table
The name "truth table" comes
from a similar table used in symbolic
logic, in which the truth or falsity
of a statement is listed for all possible
proposition conditions. The truth table
consists of two parts; one part comparising
all combinations of values of the variables
in a statement (or algebraic expression),
the other part containing the values
of the statement for each combination.
The truth table is useful in that it
can be used to verify Boolean identities.
--------------------------------------------------------------------------------
Adjacent
cells
Consider the following map. The function
plotted is 
Using
algebraic simplification 
,
by using T9a of the Boolean Laws (A
+ 
=
1). Referring to the map we can encircle
the adjacent cells and infer that A
and are not required.
If
two occupied cells of a Karnaugh are
adjacent, horizontally or vertically
(but not diagonally) then one variable
is redundant. This has resulted by labelling
the map as shown, i.e. adjacent cells
satisfy the condition A + =
1.
--------------------------------------------------------------------------------
Prime
implicants
It is an implicant of a function which
does not imply any other implicant of
the function.
-------------------------------------------------------------------------------
Prime
implicant chart
The chart is used to remove redundant
prime implicants. A grid is prepared
having all the prime implicants listed
down the left and all the minterms of
the function along the top. Each minterm
covered by a given prime implicant is
marked in the appropiate postion.
