# LOGIC CIRCUITS

**LOGIC CIRCUITS **

**Number systems and codes:** Binary, Octal and Hexadecimal number systems. Conversion from any base to another base number system. Binary, BCD, Excess-3, Alphanumeric, EBCDIC, Hollerith, ASCII codes, code conversion, error detecting and correcting codes, parity and Hamming codes.

**Binary Arithmetic:** Basic rules for addition and multiplication. Sign magnitude notation, One’s complement notation. Two’s complement notation. Addition and multiplication using binary, octal and hexadecimal number systems.

**Boolean Algebra and Logic Gates:** Boolean algebra theorems, reduction of logic expressions using boolean algebra, truth tables, minterms, maxterms, SOP and POS forms. Standard SOP and POS forms. Basic and universal logic gates, control aspect of gates, enabling and disabling of gates. K map representation of logical functions, simplification of logic functions using K-maps upto 6 variables. Quine McCluskey method and Veitch diagrams used for logic function reduction.

**Combinational Logic Circuits:** Concepts of combinational and sequential logic circuits. Realisation of following circuits using gates.:

(a) Systems implementing combinational logic.

(b) Arithmetic circuits, half and full adders, subtractors, multipliers, code converters, parity generators, parity checkers, comparators.

(c) Multiplexers, demultiplexers, encoder, decoder.

(d) Concept of mode control

(e) Application of MSI devices for multiplexer, demultiplexer/decoder, parity generator/checker, concept of capacity expansion using gates. Use of MSI devices for adders, Sequential adder, BCD adder / subtractor, carry look ahead adder, multiplier, fast multipliers, Arithmetic Logic Unit

**Sequential Circuits:** Concept of Synchronous and Asynchronous operation.

(a) Flip Flops : Basic cell, SR , clocked SR, D, T , J-K, J-K with preset and clear, Master Slave J-K flip flops. Concept of level triggering and edge triggering , flip flop excitation tables, triggering and timing of flip flops.

(b) Registers: Shift registers, bi-directional, serial to parallel, parallel to serial conversion.

(c) Analysis of clocked sequential circuits.

(d) Asynchronous counters: up-down counters, modulo N counter, glitch problem.

(e) Synchronous counters: Use of K- maps for synchronous counters, ring counters, twisted ring counters, counters using shift registers, sequence generators using flip flops.