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Alternate Logic-Gate Representations

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Alternate Logic-Gate Representations We have discussed the five basic logic gates (AND, OR, INVERTER, NAND, and NOR) and the standard symbols used to represent them in a logic circuit diagram. Most of the logic networks use standard symbols. But in some networks an alternative set of symbols is used in addition to the standard symbols. The table shows the alternate set of symbols for the five basic gates. Table: Alternate Logic Gate Representations To convert any normal symbol to its corresponding alternate symbol, the following steps are used: METHODOLOGY: TO CONVERT STANDARD SYMBOL TO ALTERNATE SYMBOL Step 1: Add bubbles (indication of inversion) at those input or output points where it is not present. Step 2: Remove all pre-existing bubbles of the normal symbol, if there is any at the point (only NOT, NAND and NOR gates) Step 3: If the existing normal logic symbol is AND, change it to OR, Similarly, if it is OR, then change it to AND. There is no change for the triangular symbol of ...
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Sequential Circuits

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We discussed various combinational circuits in earlier chapters. All these circuits have a set of output s s , which depends only on the combination of present inputs. The following figure shows the  block diagram  of a sequential circuit. Figure: S equential Circuit This sequential circuit contains a set of inputs and output s s . The output s s  of the sequential circuit depend not only on the combination of present inputs but also on the previous output s s . The previous output is nothing but the  present state . Therefore, sequential circuits contain combinational circuits along with memory  s t o r a g e s t o r a g e  elements. Some sequential circuits may not contain combinational circuits, but only memory elements. The following table shows the  differences  between combinational circuits and sequential circuits. Combinational Circuits Sequential Circuits Outputs depend only on present inputs. Outputs depend on both present inputs and pre...
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Boolean Algebra Questions with Solutions

Definition: The algebra of logic is a Boolean algebra. It works with variables with two different values, such as 0 (False) and 1 (True), as well as logically significant operations. George Boole invented the first way of manipulating symbolic logic, which later became known as Boolean Algebra. Because of its vast applications in switching theory, developing basic electronic circuits, and designing digital computers, Boolean algebra has become a vital tool in computer science. The following are the basic operations of Boolean algebra: AND or conjunction operation OR operation or disjunction Not or Negative operation Rules: Suppose X and Y are two Boolean variables, then the three operations are defined as follows; X AND Y, satisfies X ∧ Y = True, if X = Y = True or else X ∧ Y = False. X OR Y, satisfies X ∨ Y = False, if X = Y = False, else X ∨ Y = True. ¬X satisfies ¬X = False, if X = True and ¬X = True if X = False Boolean Algebra Questions with Solutions 1. Define Boolean expression....
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