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Digital Electronics
NUMBER SYSTEM
BINARY CODES
BOOLEAN ALGEBRA
BINARY LOGIC
LOGIC GATES
BOOLEAN ALGEBRA LAWS
CONSENSUS THEOREM
DIFFERENT FORS OF BOOLEAN EQUATIONS
RELATION B/W MAX & MIN TERMS
16 type of LOGIC FUNCTIONS
AND & OR GATE
Other GATES
XOR & XNOR gates
NEGATED & COMPLIMENTRY GATES
TRISTATE gates & DIP
Illustration of NEGATIVE & POSITIVE LOGIC
Relation B/W XOR & XNOR gates
UNIVERSAL GATES
Implementation of XOR using minimum gates
Implementation of XNOR using minimum gates
Different levels of CIRCUIT
Special Characteristics of an IC
QUESTIONS
Q1 (Timing Diagram)
Q2 (Timing Diagram)
Q3 (Timing Diagram - DIfferent units)
Q4 (Timing Diagram)
Q5 (Output of Series of NOR gate )
Q6 (Output of combination of XOR )
Q7 (Circuit of NAND gates & diff delays)
K MAPS
COMBINATIONAL CKT
SEQUENTIAL CIRCUITS
TIMING CIRCUITS

 

 

Tristate gates:

These are the special gates which give 3 kinds of outputs: low, high, high impedance (Z). Such gates have an extra input which is called enable input.

When enable input is high, switch is closed & tristate buffer act as a normal buffer and when enable input is low output is high impedance state (floating). Following is the truth table:

Dual Inline Packaging (DIP): All the digital logic gates are manufactured as integrated circuits means all the transistors and resistors are mounted on a single piece of semiconductor and then put in Dual Inline Packaging (DIP). There is an industry standard about naming the ICs. The general format for the TTL IC is as.

  • First two letters are used to specify the manufacturers’ name e.g. ST is used for company named ST microelectronics.
  • Then we have 74/54 for TTL ICs. 74 is used for normal use ICs while 54 ICs are military-grade ICs and have higher operating temperature and are robust in voltage levels.
  • Next 2-letter tells us about the circuitry. E.g. LS is used for Low power Schottky i.e. schottky diodes and transistor are used in the circuitry to decrease the power supply.
  • And next letter tell us about the function of the IC e.g. 08 is for AND gate

Hence we have the complete name as ST74LS08


 


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