You are working as an engineer for a company of your choice. Your supervisor has put you in charge of the following project as a result of a client request:

Your line manager has informed you that a company client requires you to design a d.c. power supply unit (PSU) with dual output voltages of  ± 5 V, ± 12 V (d.c.) and with maximum power of 50 VA . A tight budget of  £35 was allocated for the required components for this unit.  

Your task:

Step 1: Identify two PSU design circuits that would meet the client's specifications.

For each PSU clearly specify the following:

a. AC input voltage

b. Input frequency (preferably 50 Hz)

c. Output DC voltages

d. DC power output

e. Input Power Factor (P.F)

f. The estimated cost of each proposed PSU

In addition, give a full account of your research into the PSU circuits and provide a list of sources you have used in your research.

Step 2: Establish and identify the full specifications and procedures for the project to design, build and evaluate the chosen PSU circuit. Present your answer in a form of a project plan.

Step 3: Simulation and Testing

1. Create a log book in which you will record all procedures, activities and results for steps 3 to 5.

2. Simulate the PSU circuits using either Multisims, PSpice or any other simulation tool to verify all your test measurements at both input and output terminals of the PSU should be provided.

Record and collate simulation data obtained.

Step 4: Having conducted simulation testing, evaluate the above PSU circuits in terms of their design specifications in step 1. Decide which PSU circuit you are going to build for your client. You also have to take into account which PSU will be the best choice for your client in terms of meeting their requirements, efficiency and cost effectiveness. Justify your reasons for selecting this PSU. 

Step 5: Build a working external (desktop) PSU to the chosen specifications on the vero-board. Your built PSU circuit should be enclosed inside an aluminium or plastic box with appropriate AC mains input leads and socket. The output DC (both +/- 5 v and +/-12v) should be connected to an appropriate terminal. Consider based on the most efficient and cost effective design. Test your PSU in real time, record results and compare them with results obtained during the simulation stage. Interpret and justify the results in terms of the original specifications.

Step 6 Prepare a final project report with all appropriate circuit, block diagrams and input and output signal waveforms etc.  There is no set length but your report should not exceed 10-15 pages. Your report should contain a self-evaluation statement specifying what you have learnt during the project and what you would have done differently if you were to conduct this or similar project in the future. Your conclusion should be open-ended to allow further product development.