International Journal of Engineering Research and Development e-ISSN: 2278-067X, p-ISSN: 2278-800X, www.ijerd.com Volume 9, Issue 2 (November 2013), PP. 22-29 22 The Computer Architecture of a Microcontroller Based Transistor Tester with a Logic Display Aru Okereke Eze 1 , Opara, F.K 2 . 1 Department of Computer Engineering Michael Okpara University of Agriculture, Umudike, Umuahia, Abia State, Nigeria 2 Department of Electrical/Electronics Engineering Federal University of Technology, Owerri, Imo State, Nigeria Abstract:- This work exploits the design and implementation of a microcontroller based transistor tester with a logic control. Microcontroller based transistor tester is a device used to test the electrical behaviour of transistors and diode states within transistors. The transistor device is commonly used for circuitry and electronics. Most transistor testers test whether or not a transistor is sinking input (NPN) or sourcing output (PNP). This work is aimed at designing a microcontroller based transistor tester required to test Bipolar Junction Transistor, Field Effect Transistor and Uni-junction Transistor. It is also aimed to experimenting and producing a well reliable transistor, not only testing Bipolar, Field Effect and Uni-junction transistor but also other electronics component useful in daily human lives. Keyword:- Microncontroller, Transistor Tester, Liquid Crystal Display, Adc0804, Cpu, Rom, Ram, Etc. I. INTRODUCTION A microcontroller is an integrated chip that is often part of an embedded system. The microcontroller includes a CPU, RAM, ROM, I/O ports, and timers like a standard computer, but because they are designed to execute only a single specific task to control a single system, they are much smaller and simplified so that they can include all the functions required on a single chip. Microcontrollers have become common in many areas, and can be found in home appliances, computer equipment, and instrumentation. They are often used in automobiles, and have many industrial uses as well, and have become a central part of industrial robotics and most especially in the design of a transistor testing devices. Microcontroller based transistor tester is a device used to test the electrical behaviour of transistors and diode states within transistors. The transistor device is commonly used for circuitry and electronics. Most transistor testers test whether or not a transistor is sinking input (NPN) or sourcing output (PNP). A microcontroller based transistor tester is used to test bipolar junction transistors. It uses a method to type, pin and check for forward direct current (DC) gain. It can be used to test field effect transistor. A FET can be tested using a transistor tester and is needed wherein the correct biasing voltages can be applied and the tester display can reveal the full operating characteristics of the device. And also it can test Unijunction transistor by checking the resistance between B1 and B2. II. SYSTEM METHODOLOGY It is noted that the project is Micro-controller based, with some discrete components. A liquid crystal display (LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. Its uses include monitors for computers, televisions, instrument panels, and other devices ranging from aircraft cockpit displays, to every-day consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones. Among its major features are its lightweight construction, its portability, and its ability to be produced in much larger screen sizes than are practical for the construction of CRT display technology. III. SYSTEM DESIGN There are different methods which were adopted in this project study which are as follows: The memory unit/micro-controller AT89C52 microcontroller Micro-controller pin descriptions 3.1 THE MEMORY UNIT/ MICRO-CONTROLLER