Review of the Project

Initial Planning

Our group had planned to design a binary code(BCD) to Gray code converter. This idea was first proposed by me(Loh Yung Jia). At first we thought that it was very easy to do it, because we had learned it in one of our lecture. In order to convert 3 bits binary to Gray code, it requires 2 XNOR gates. So, we decided to convert 4 bits, which requires 3 XNOR gates. The IC used in the converter is a quad two-input XNOR gates IC(74LS86). An initial schematic circuit diagram was proposed & drawn by me. The diagram is then checked by Mr. Lee, lecturers of electronic engineering. The initial design faced some problems: it lacks some components. By adding these additional components, the schematic circuit diagram is then drawn and checked by Mr. Lee. Eventually, the design should be working.

Details of the design

This converter containes 8 L.E.D.s, 12 resistors, 3 capacitors, 4 two-pole switches, 1 IC(74LS86), a transistor() and a 9V battery. The 4 switches provide the input of 4 bit binary code. Switch ON=input logic 1, switch OFF=input logic 0. There are 16 possible combination of inputs for a 4-bits binary code. The 4 input LEDs(green) indicates the code that user input. LED ON=logic 1, LED OFF=logic 0. The resulting Gray code is shown by another set of 4 LEDs(red).


Schematic diagram of circuit