EE331L: Analog Electronics II

A DC Power Supply


AC power has been historically used for transmission across long distances without significant losses, but almost all electronics applications require DC power to run the circuits. Hence DC Power supplies are possibly one the most important components of electronic circuits. You will have to design and implement an AC-DC converter.


  1. Build an AC-DC converter

  You are to design, simulate and implement an AC-DC converter.

  You may use your own design and may choose from any components present in the teaching lab.

  The input signal will be a 60Hz Sinusoid with 9Vrms at up to 700mA from the supplied isolation transformer. Note that shorting the transformer output leads will quickly result in a failed transformer. An inline, one-amp fuse will protect the transformer from damage.

  Your circuit must output a variable 1, 2.5 and 5 VDC signal capable of driving a 50 Ohm load resistor.

  You cannot use a separate DC power supply to power any active devices. If you choose to use active components (for example: to provide voltage regulation), they must be powered by your own supply.

  1. Test your circuit

  Once you have built your circuit to your satisfaction, you will test your power supply.

  For a given output voltage you should drive a 100 K resistive pot as a load, in series with a 50-ohm resistor.

  Your circuit must not exceed 1% offset voltage, or ripple voltage.

  If you choose the output voltage to be 1 V, for instance, the output voltage offset should be less than 10 mV for all values of the resistive pot. You should show this for all 3 output voltages.

  For a given output voltage, the ripple amplitude on that voltage should be less than 1% for all values of the resistive pot.

Analysis and Report:

Please complete a lab report. Focus on explaining your design process. Explain how you chose the overall circuit design and the key components. Explain the important parameters and effects of your circuit, as well as how it could be improved in the future, or with more resources. Your report should address the following:

  Circuit Diagram

  Waveforms (both simulated and measured, voltages and currents)

  Power considerations

  Voltage regulation, ripple, rectification, etc.

  Component tolerances (Hint: use a Monte Carlo simulation)


Your lab report will be due one week after the 2-session lab period.