Chapter 4 Combinational Logic

**Logic Diagram Of 2 To 4 Decoder**- Watch video · Let us build the 2:4 decoder circuit diagram on breadboard and check how it is working in real life. To make it work as a hardware you have to use the logic gate IC like 7404 for NOT gate and the 7408 for the AND gate .. 2 to 4 decoder is used to select 1 output lines out of 4 available based on data on two input lines. Following table mentions the logic behind this. If both inputs are set to. So, if n represents given input lines then possible output lines would be 2 n . Decoder with three inputs would give 8 outputs (n=2,2 3 that is 8). Step 1. Now we know possible outputs for 3 inputs, so construct 3 to 8 decoder , having 3 input lines, a enable input and 8 output lines..

Tutorial. 2 bit to 4 line decoder with active low output One thing that is really common in computers are sequences. Things happen, one after the other, in an ordered, regular, pattern.. Figure 1 shows the circuit diagram of a 4-bit, 4-line to 16-line decoder using two 7422 4-line to 10-line decoder IC . The input A, B, C and D can represent any logic function and the output 1 through 16 will then provide the addition or the logic or function of these four inputs.. Problem: Question 1- Draw the logic diagram of a 2 to 4 line decoder using a) NOR gates only b) NAND gates only. Include an enable input. Question 2- Describe the logic diagram of encoder..

logic diagram; (b) logic symbol Bus transceiver: contains pairs of tri-state buffers connected in opposite directions: from A to B if DIR=1, or from B to A if DIR=0 Buffers are enabled only if G_L=0 The circuit is used typically between two busses.. Decoder is a circuit that convert binary information from n-input lines to max of 2 n output lines e.g. if we have 2 inputs i.e. x,y then there will be 4 output of a Decoder and size of Decoder will be 2X4.. Combinational Logic Circuit Design Even though CAD tools are used to create combinational logic circuits in practice, it is important that a digital designer should learn how to generate a logic circuit from a specification..

Here you have 2 inputs, 4 outputs, 4 ANDs, 2 NOTs, each AND has 2 inputs. Now you have to think how can you turn 4 inputs into 3 to make this thing work. Well basically what you need is an enable switch at the gates, a switch that will enable when a gate is LOW (0) or HIGH (1).. Logic diagram for a 2× 4 decoder, just use gates. Include logic for enable input. Grading Note: Several students had the correct logic diagram fur the decoder, but then OR’d together. (b) Draw a block diagram and truth table of a full 2-bit binary decoder, (2-line- to-4-line decoder). [4 marks] (c) With the aid of a simple diagram, explain what is meant by a multiplexer..

Spring 2011 ECE 331 - Digital System Design 21 2-to-4 Decoder with Enable. Spring 2011 ECE 331 - Digital System Design 22 Encoders. Spring 2011 ECE 331 - Digital System Design 23 Encoders Use an n-output decoder to realize a logic circuit for a function with n minterms.. these cases the output to an inverted 2-4 line decoder would be like this. Fig 1 shows the symbol of decoder and fig 2 schematic of decoder gate level diagram..