Design a power supply to convert standard UK mains to a given D.C. voltage and maximum current
DC voltage been 12V. And maximum current been 4 Amp.
Remember that the input voltage 240V A.C, which is 325V RMS this is useful when designing the transformer.
Your design should include:
1. A simulation or preferably simulations showing how your design has been refined to meet the specification and any improved values that have been introduced when real components are identified. The simulations should be done in LT Spice.
2. A description of the operation with simple calculations based on an appropriate transistor model (include the emitter resistance concept).
3. Describe the performance of your design under load and show how much the output voltage falls between no-load and maximum load conditions (assuming a simple resistive load). Also identify the magnitude of the ripple under maximum load.
4. Identify real components to build the power supply and if possible update the design with more realistic values of properties such as winding resistance, transistor current gain etc.
5. Check that the components have adequate current and voltage ratings and find the power dissipated in the transformer and the transistor under maximum load.
6. Investigate any heat-sink that would be required for your power transistor and confirm that the transistor junction temperature would remain safely below the maximum. Indicate whether the transistor heat-sink assembly would need to be externally mounted etc.
7. Provide a rough costing of the parts for your design.