DESIGN AND CONSTRUCTION OF A VARIABLE'BIPOLARITY POWER SUPPLY UNIT WITH DIGITAL DISPLAY METER

Abstract

This project is based on the design and construction of a regulated - 15 Volts to + 15 Volts variable DC power supply with digital readout. The power supply was designed and constructed with a ripple voltage of 50m V and a power rating of 30 watts. It was designed and constructed to display the output voltage of the variable DC power supply in digital form. The regulated variable DC power supply is a special type of DC power source which supplies electronic devices of different voltage input at different time; hence it is more compact and economical than different rated DC power supply . . This makes it very useful in the laboratory for performing experiment~ where different voltages will be needed at different time. It consists of the following six major components, which are the transformer, rectifier, filter, voltages regulator, analog to digital converter with inbuilt seven segment decoder and the seven segment display. Loading test were carried out on the power supply and the graph of current against voltage were plotted. From the results obtained, it was seen to obey Ohm's Law.