Complex diode circuit

• Engineering

Homework Statement

Consider the following power supply circuit, which uses typical component values. The
diodes have a forward drop of 0.6V each. Transformer voltages are RMS (root mean
square).

http://img294.imageshack.us/img294/1665/70454661.png [Broken]

a. Determine the DC output voltage under ‘no load’.
b. Determine the amplitude of the ripple when a current of 200mA is drawn from the
supply.
c. What should the current “rating” of the supply be, if the ripple (peak-to-peak)
must be kept below 1% of the output voltage?
d. Find the average power dissipated in the circuit assuming ω = 300 rad/s.

unsure...

The Attempt at a Solution

Honestly, I'm just not really sure where to actually -start- on this. We barely touched on this material in class and our text (Principles of Electronics Analog and Digital) is fairly lacking in any sort of examples to try to follow the logic. I just need some tips on how to approach this problem from a fundamental standpoint, really, so if you can just give some tips on how to start with it, I can probably carry on.

Last edited by a moderator:

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berkeman
Mentor

Homework Statement

Consider the following power supply circuit, which uses typical component values. The
diodes have a forward drop of 0.6V each. Transformer voltages are RMS (root mean
square).

http://img294.imageshack.us/img294/1665/70454661.png [Broken]

a. Determine the DC output voltage under ‘no load’.
b. Determine the amplitude of the ripple when a current of 200mA is drawn from the
supply.
c. What should the current “rating” of the supply be, if the ripple (peak-to-peak)
must be kept below 1% of the output voltage?
d. Find the average power dissipated in the circuit assuming ω = 300 rad/s.

unsure...

The Attempt at a Solution

Honestly, I'm just not really sure where to actually -start- on this. We barely touched on this material in class and our text (Principles of Electronics Analog and Digital) is fairly lacking in any sort of examples to try to follow the logic. I just need some tips on how to approach this problem from a fundamental standpoint, really, so if you can just give some tips on how to start with it, I can probably carry on.
First, convert the output RMS voltage number to a peak-to-peak AC voltage number. That is the input waveform to the bridge. Then figure out what the output DC no-load value would be -- it's related to the AC p-p input to the bridge, and to some number of diode drops. Picture what the bridge does when the AC waveform in is at it's positive peak value, and then at its negative peak value...

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