23-01-2013, 04:42 PM
DIGITAL BASIC IC TESTER
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Abstract
The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table. It can test digital ICs having 14 pins. Our main aim is to design the model using only digital IC’s that were known to us at our second year of B.Tech course. This model applies the necessary signals to the inputs of the IC, monitoring the outputs at each stage and comparing them with the outputs in the truth table. Any discrepancy in the functioning of the IC results in a fail indication through LED. The testing procedure is accomplished with the help of keys present on the main board. At this stage we had completed to test the most common used digital IC's used in our laboratories, mainly belonging to the 74TTL series .This tests various types of IC's like AND,OR, EX-OR, NAND, NOR and EX-NOR gates.
INTRODUCTION
In any manufacturing industry there are continuous efforts in cost reductions, upgrade quality and improve overall efficiencies. In electronic industry, with dramatic increase in circuit complexity and the need for the higher levels of reliability, a major contributor cost in any product can be in the testing. However we should recognize in the real world that no product is perfect, so that testing and in particular automatic testing will be an essential part of production in the foreseeable future. In industries, research centers and college, some common IC's are frequently used; many times people face problems due to some fault in these integrated circuits. So it is very essential to test them before actually using them in any of the applications. Digital IC tester is best solution for these problems. This project has the capability of testing digital IC’s like AND, OR, EX-OR, NAND, NOR and EX-NOR gates of 14 pins.
BACKGROUND OF DIGITAL IC TESTER
The digital IC tester is implemented in order to test the digital IC’s to verify the faulty gates and the good gates. The necessary inputs to the gates of the IC to be tested which is placed in the test socket and corresponding outputs are accumulated and sent to the inequality detector where the output is compared with the logic table and if any discrepancy results, it displays the fail through LED. The primary purpose of this digital IC tester is that it can easily check the IC within due course of time and if any discrepancy results then it determines the gates which were good ones and which were the bad ones. The manual operation or a human intervention includes testing of each individual IC by making necessary connections and verifying the outputs for each gate by the truth table is a time taking and tedious process. With the implementation of the memory unit it makes the job much easier to receive data for the respective gates and process output and display results.
Output- generator
As the main aim is to construct this tester using only digital ICs and without any microcontroller or any other memory unit, a combinational circuit is designed to produce the outputs of various gates according to the inputs provided by the MOD-4 synchronous Counter. A multiplexer can be used in place of logic gates to implement a logic expression. It can be so connected that it duplicates the logic of any truth table, i.e. it can generate any Boolean algebraic function of a set of input variables. In such applications, the multiplexer can be viewed as a function generator, because we can easily set or change the logic function it implements. One advantage of using a multiplexer in place of logic gates is that,a single integrated circuit can perform a function that might otherwise require numerous integrated circuits.
CONCLUSION
The project has been successfully completed and the main objective of emulating an IC tester using only digital ICs has been achieved. This would be more successful if it tests some more ICs.
[attachment=48215]
Abstract
The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table. It can test digital ICs having 14 pins. Our main aim is to design the model using only digital IC’s that were known to us at our second year of B.Tech course. This model applies the necessary signals to the inputs of the IC, monitoring the outputs at each stage and comparing them with the outputs in the truth table. Any discrepancy in the functioning of the IC results in a fail indication through LED. The testing procedure is accomplished with the help of keys present on the main board. At this stage we had completed to test the most common used digital IC's used in our laboratories, mainly belonging to the 74TTL series .This tests various types of IC's like AND,OR, EX-OR, NAND, NOR and EX-NOR gates.
INTRODUCTION
In any manufacturing industry there are continuous efforts in cost reductions, upgrade quality and improve overall efficiencies. In electronic industry, with dramatic increase in circuit complexity and the need for the higher levels of reliability, a major contributor cost in any product can be in the testing. However we should recognize in the real world that no product is perfect, so that testing and in particular automatic testing will be an essential part of production in the foreseeable future. In industries, research centers and college, some common IC's are frequently used; many times people face problems due to some fault in these integrated circuits. So it is very essential to test them before actually using them in any of the applications. Digital IC tester is best solution for these problems. This project has the capability of testing digital IC’s like AND, OR, EX-OR, NAND, NOR and EX-NOR gates of 14 pins.
BACKGROUND OF DIGITAL IC TESTER
The digital IC tester is implemented in order to test the digital IC’s to verify the faulty gates and the good gates. The necessary inputs to the gates of the IC to be tested which is placed in the test socket and corresponding outputs are accumulated and sent to the inequality detector where the output is compared with the logic table and if any discrepancy results, it displays the fail through LED. The primary purpose of this digital IC tester is that it can easily check the IC within due course of time and if any discrepancy results then it determines the gates which were good ones and which were the bad ones. The manual operation or a human intervention includes testing of each individual IC by making necessary connections and verifying the outputs for each gate by the truth table is a time taking and tedious process. With the implementation of the memory unit it makes the job much easier to receive data for the respective gates and process output and display results.
Output- generator
As the main aim is to construct this tester using only digital ICs and without any microcontroller or any other memory unit, a combinational circuit is designed to produce the outputs of various gates according to the inputs provided by the MOD-4 synchronous Counter. A multiplexer can be used in place of logic gates to implement a logic expression. It can be so connected that it duplicates the logic of any truth table, i.e. it can generate any Boolean algebraic function of a set of input variables. In such applications, the multiplexer can be viewed as a function generator, because we can easily set or change the logic function it implements. One advantage of using a multiplexer in place of logic gates is that,a single integrated circuit can perform a function that might otherwise require numerous integrated circuits.
CONCLUSION
The project has been successfully completed and the main objective of emulating an IC tester using only digital ICs has been achieved. This would be more successful if it tests some more ICs.