Design And Construction Of An Ac/Dc Voltage Power Supply Trainer Kit

INTRODUCTION
1.1 BACKGROUND STUDY
Although certain electrical appliances operate with an unregulated AC, almost all basic household and laboratory electronic circuits need an unregulated AC to be converted to constant DC, in other to operate the electronic device. The AC supply from the mains is usually rectified to a DC, and the DC supply is regulated and limited in terms of voltage and current. But the supply provided from the mains may be fluctuating and could easily break down the electronic equipment if not properly limited. This work of converting an unregulated alternating current or voltage to a limited direct current or voltage to make output constant regardless of the fluctuations in inputs is achieved by regulated power supply trainer circuit.
Power supply trainer circuit board’s fundamental base is providing both unregulated AC power for AC operated devices and a Variable DC for operation of basic electronic devices as well as provide circuitry components for carrying out of certain electrical test, experiments and training in the laboratory.

1.2 APPLICATION OF THE PROJECT
Some applications of power supply trainer are:
Supply of electric power for operation of laboratory appliances using AC;
Achieving dc supply of electrical power ranging from 0.2V to 24V;
For testing of components, which makes it easy to design prototypes and experiment with circuit designs.
The LM317 voltage regulator used has many electrical applications. Here are the few of the applications
i. Energy harvesting
ii. Refrigerator
iii. Power quality meter
iv. Power substation control
v. HVAC (Heating Ventilation Air Conditioning)
vi. Signal and wave generation
vii. Ethernet switch

1.3 AIM OF THE PROJECT
The aim of this project is to construct an AC-DC power Supply Trainer Board.

1.4 OBJECTIVES OF THE PROJECT
To design and construct a trainer board which receives electrical AC power from the mains.
To design and construct a circuit with a set of diodes that rectifies the ac to a dc.
To design and construct a circuit that regulates the rectified dc voltage and varies the out with voltages ranging from 0.2V to 24V. To mount several electrical components such as meters, plug sockets, active and passive components like resistors, capacitors and inductors.

1.5 LIMITATION OF THE PROJECT
Though the power supply trainer can be used for operating of several dc devices, it can also be used for laboratory purposes and is therefore for internal use only. The selection of ac taps is done manually, that is, by connecting from one tap to another.

1.6 SIGNIFICANCE OF THE PROJECT
i. It is a positive voltage regulator
ii. It provides multiple tap output
iii. It has internal current limiting
iv. Thermal shutdown
v. Safe area compensation
vi. The materials and components for this project are affordable and readily available in electronics stores.

1.7 METHODOLOGY
To achieve the aim and objectives of this work, the following are the steps involved:
i. Study of the previous work on the project so as to improve it efficiency.
ii. Draw a block diagram.
iii. Test for continuity of components and devices,
iv. Design and calculation for the device was carried out.
v. Studying of various component used in circuit.
vi. Construction of the circuit was carried out.
vii. Finally, the whole device was cased and final test was carried out.

1.8 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.