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 to 5 VDC signal capable of driving a 50 Ohm load resistor.

  You cannot use the DC power supply to power any active devices. If you choose to use active components, they must be powered by your own supply.

  Capture test waveforms from your amplifier before the competition.

  1. Test your circuit

  Once you have built your circuit to your satisfaction, we will test all of those circuits on the same platform.

  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 amplitude.

  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 voltages between 1-5 Volts.

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

  Once you have met the above requirements, the competition will be to show the circuit that is able to drive the lowest load resistance without exceeding the 1% error

Analysis and Report:

Please complete a brief lab report (2-3 pages). 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)

  Power considerations

  Voltage regulation, ripple, rectification, etc.

  Component tolerances (Hint: use a Monte Carlo simulation)


Your lab report will be due in one week.