Design and Development of Stabilized Regulated Fixed and Variable DC Power Supply Unit (PSU) With Short Circuit Protection

A Fixed Regulated Power Supply, a Variable Regulated Power Supply and a Dual Regulated Power Supply are constructed by using transformers, Diodes, Capacitors, ICs and Variable resistors. Therefore, the purpose of this study is to design and develop a Variable Voltage Power Supply from Fixed Voltage Regulator that is single and dual power supply with a voltage of 5 V fixed DC, 0.25V to 15.0V variable DC, +12 V and -12V dual power supply and current range of 0 to 1Amps, power 45W with a very low output impedance of 0.010ohms with short circuit protection. This project report will be approached primarily by literature and practical research. Focusing firstly on gaining a wide and comprehensive understanding of the chosen study area, a literature review was completed. Results found also showed the load and line regulation characteristics of a constructed power supply so as to determine its stability by comparing it with standard power supply unit. Testing of constructed power supply unit to power loads (Rheostat) of 120ohms 1A and 10ohms 0.5A. The major components used include step down transformers (Input 230V AC, Output 12V AC, Output 24V AC), 1N4007 Diodes, Capacitors, ICs (7805 IC, 7812 IC, 7912 IC and LM317 IC,) and fixed & Variable resistors i.e. potentiometer, transistors. The developed power supply is tested for its functionality and the measured values are compared with nominal designed values. The designed power supply is much useful in measurements, laboratory works and general applications requiring power supply.