DEVELOPMENT OF SMART TOOLS FOR TRANSISTOR TESTER. NUR SYAFIQAH BINTI ABDULLAH POLITEKNIK SULTAN SALAHUDDIN ABDUL AZIZ SHAH

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1 DEVELOPMENT OF SMART TOOLS FOR TRANSISTOR TESTER NUR SYAFIQAH BINTI ABDULLAH POLITEKNIK SULTAN SALAHUDDIN ABDUL AZIZ SHAH ZAKIAH BT MD SAAD POLITEKNIK SULTAN SALAHUDDIN ABDUL AZIZ SHAH FA'IZAH BT YA'ACOB POLITEKNIK SULTAN SALAHUDDIN ABDUL AZIZ SHAH ABSTRACT Transistor is a simple semiconductor device with complicated behaviour. It consist of 3 pins Emitter, base and collector, can be tested using multimeter in a long and time consuming procedure. This resulted to the students performance while conducting the experiments and delayed the understanding of the students regarding this electronics components. In order to overcome this problem In-Circuit Transistor Tester has been developed to assist the lecturers and students examining transistor. It can be done while transistor is still in the circuit without have to pulled it out which can effect and damage the device. As it will save the time taken during conducting long experiment, it also simply the procedure and reliable. This tester has been executed in 3rd semester class of Electronic Equipment Repair Course (DEE3052) at Electrical Engineering Department, Polytechnic Sultan Salahuddin Abdul Aziz Shah. It has proven the proposed device, In-Circuit Transistor Tester, experiment conducted during practical hours run effectively, smooth and quick. KEY WORDS: Transistor, In Circuit Transistor Tester, Emitter, Collector 1. INTRODUCTION Electronic testing and its equipment are essential elements in electronics and radio. To determine whether the circuit is working and to identify where the problem lies, it is necessary to use forms of testing equipment. Goods testing equipment commonly are analogue and digital multimeters, oscilloscope, and under certain circumstances, more specialized test equipment including spec-trum analyzers can be used. Conventionally fault finding for electronic devices was done using the multimeter. Although it will not be possible to resolve all the problems using a multimeter, it is one of the basic tools which is very useful to find the error. An accurate reading cannot be produced when testing a transistor that still on pcb circuit. This is because many other component in the circuit can affect the result, unless it the transistor remove from circuit. Testing procedures outside the circuit is quite complicated and requires more time. In addition it can cause a broken leg transistor when it is assembled and disassembled repeatedly. Soldering and disoldering abilities of students also a significant process to perform this procedure.

2 Therefore, to enable students to test transistor without unplugging it from the circuit, a testing device called ICTT is designed to test the electrical behavior of the transistors. It can be used to check whether a transistor is still operational. The transistor's ability to "amplify" is taken as a rough index of its performance. This type of tester indicates to a Lecturer and students whether the transistor is dead or still operative. The advantage of this tester is that the transistor does not have to be removed from the circuit. 2. LITERATURE REVIEW A transistor is a semiconductor that allows current to flow through it under certain conditions, and cuts current off when other conditions are present. Transistors are commonly used as either a switch or a current amplifier. You can test a transistor with a multimeter that has a diode test function. The diode test using an analogue multi-meter can be extended to give a simple and straight forward confidence check for bipolar transistors. The test relies on the fact that a transistor can be considered to comprise of two back to back diodes, and by performing the diode test between the base and collector and the base and emitter of the transistor using an analogue multi-meter, the basic integrity of the transistor can be as curtained. It should be noted that a transistor cannot be functionally replicated using two separate diodes because the operation of the transistor depends upon the base which is the junction of the two diodes, being one physical layer, and also very thin (ElectronicNotes, 2016). This is a conventional method how to test transistor using a multi-meter. Firstly, set the meter to its ohms range - any range should do, but the middle ohms range if several are available is probably best. Connect the base terminal of the transistor to the terminal marked positive (usually coloured red) on the multi-meter. Connect the terminal marked negative or common (usually coloured black) to the collector and measure the resistance. It should read open circuit (there should be a deflection for a PNP transistor) (wikihow, 2016). With the terminal marked positive still connected to the base, repeat the measurement with the positive terminal connected to the emitter. The reading should again read open circuit (the multi-meter should deflect for a PNP transistor). Now reverse the connection to the base of the transistor, this time connecting the negative or common (black) terminal of the analogue test meter to the base of the transistor. Connect the terminal marked positive, first to the collector and measure the resistance. Then take it to the emitter. In both cases the meter should deflect (indicate open circuit for a PNP transistor) (wikihow, 2016). It is next necessary to connect the meter negative or common to the collector and meter positive to the emitter. Check that the meter reads open circuit. The meter should read open circuit for both NPN and PNP types. Now reverse the connections so that the meter negative or common is connected to the emitter and meter positive to the collector. Check again that the meter reads open circuit. If the transistor passes all the tests then it is basically functional and all the junctions are complete. The final checks from collector to emitter ensure that the base has not been "blown through". It is sometimes possible that there is still a diode present between collector and base and the emitter and the base, but the collector and emitter are shorted together (Ryinejan, 2015).

3 Figure 1: Conventional Method Of Measuring Transistor (ElectronicNotes, 2016) 3. METHODOLOGY This project was developed from the first step of producing the circuit design layout until it was ready to be tested. Figure 2 shows the flowcharts of ICTT project development. The circuit has been designed using simulation software PROTEUS to observe circuit performance. The project board was prepared and the component was soldered on it. The completed circuit was tested. Start Design the circuit layout Component soldering on the PCB Testing Circuit Produced block diagram Simulation project using proteus software Function YES Fix the circuit board in the casing NO End Figure 2: Flow Chart of The Project Figure 3 show the block diagram of the transistor tester. Power supply is a device that automatically supply electrical power to the electrical appliances. The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide two or four timing circuits in one package. The J-K flip-flop is the most versatile of the basic flip-flops. It has the inputfollowing character of the clocked D flip-flop but has two inputs, traditionally labelled J and K. If J and K are different then the output Q takes the value of J at the next clock edge. Transistor for testing is a component under test to identify type and fault of the component. Rectifier is an electrical device

4 that converts an alternating current into a direct one by allowing a current to flow through it in one direction only. Output of the tester is using the electronic devices that emits light when electric current is applied called LED. Power supply Timer 555 JK Flip Flop Transistor For testing Output Rectifier Figure 3: Block Diagram Of Transistor Tester The circuit as shown in figure 4 has been tested and develop by software Proteus Figure 4 : Tested Schematic Circuit Figure 5 show the output from simulation. The output that can indicate the condition of a transistor by using two LEDs. A good NPN transistor conducts during the positive half cycle (pulses are generated by 555 dual timer) and D5 is off while D6 flashes. With a good PNP transistor D6 is off and D5 Flashes.

5 Figure 5 : Output From Simulation Using Proteus Software The Figure 6 was showing how to test a transistor in circuit board by using the ICTT. The transistor can be known through the LED display. If led in good condition, the testing process is complete. If it is damaged, changed the led to a new one. Start Test Transistor Using In- Circuit Transistor Tester (Ictt) Condition Of Transistor Refering To Led Indicator In Ictt Problem Change The Transistor End Good Figure 6: Flow Chart Of How To Test A Transistor In Circuit Board

6 4. ANALYSIS AND RESULT The status of the LEDs D1 and D2 reveals the condition of the transistor under test. If red LED is ON, It indicates that the transistor under test is a good NPN. If green LED is ON, it indicates that the transistor under test is a good PNP. If both LEDs are ON, it indicates that the transistor under test is short. If both LEDs are OFF, it indicates that either the transistor is open circuit. Table 1: Result of Transistor Testing LED (GREEN) ( ( LED (RED) ( ( CONDITION good good short circuit open circuit TYPES NPN PNP : The LED should be blinking continuously. If the pot is adjusted, then LED should be blinking at a different frequency and so both should have relation. The conditions for Transistor not working when the LED is off continuously and LED is on continuously (not. 5. CONCLUSION The conventional transistor testing must go through several processes. so it takes a long time to complete the practical work. This method can also cause damage to the transistor. Using the In circuit transistor tester during practical sessions students can save time, reduce costs and streamline the process of teaching and learning. Students can understand more easily the type of transistor and it also can reduce damage to transistor.

7 REFERENCE Book C.W.Lander. (1987). Power Electronics. London: McGraw-Hill. Goldwasser, S. M. (1998). Troubleshooting and Repair of Consumer Electronics Equipment. In D. T. Horn, Test Equipment Projects. McGraw-Hill. Hunter, a. T. (1970). Handbook of Semiconductor Electronics. ISBN Electronic Source ElectronicNotes. (2016). Retrieved from How to test a transistor with a multimeter: wikihow. (2016). How to Test Transistor, Ryinejan. (2015). Transistor Test Using an Analogue Multi Meter. scribd. BIBLIOGRAPHY AUTHOR Nur Syafiqah Binti Abdullah Lecturer of Electrical Engineering Department Politeknik Sultan Salahuddin Abdul Aziz Shah Alam Selangor, she was born in Ranau, Sabah. She received the Bachelor s degrees from the University of Open University Malaysia, her areas of research interest are in Electronic Equipment Repair and Semiconductor Devices. Experience as Finale Project Supervisor. Zakiah Md Saad Lecturer of Electrical Engineering Department Politeknik Sultan Salahuddin Abdul Aziz Shah Shah Alam Selangor, she was born in Permatang Pauh, Pulau Pinang. She received the Bachelor s degrees from the University of Technology Malaysia (UTM), Skudai and Master s degrees from Universiti Teknologi MARA (UiTM), Shah Alam, her areas of research interest are in control system, power electrics and communications. Fa izah Binti Ya acob Lecturer of Electrical Engineering Department, Politeknik Sultan Salahuddin Abdul Aziz Shah, Shah Alam Selangor, she was born in Malacca, she was graduated Bachelor Degree of Science of Electrical Engineering (Control & Instrumentation), expertise area of PLC & Automation System, Embedded System, Instrumentation and Equipment repair. Experience as Finale Project Supervisor, control and PLC