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Basic AC-DC Power Supplies
31 questions By Tony R. Kuphaldt
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Question 25 of 31
The ripple frequency of a half-wave rectifier circuit powered by 60 Hz AC is measured to be 60 Hz. The ripple frequency of a full-wave rectifier circuit powered by the exact same 60 Hz AC line voltage is measured to be 120 Hz. Explain why the ripple frequency of the full-wave rectifier is twice that of the half-wave rectifier.
Reveal answerThere are double the number of pulses in the full-wave rectifier’s output, meaning the wave-shape repeats itself twice as often.
Notes:I have heard students concoct very interesting (and wrong) explanations for why the two frequencies differ. One common misconception is that is has something to do with the transformer, as though a transformer had the ability to step frequency up and down just as easily as voltage or current! If students are not understanding why there is a frequency difference, you might want to help them out by asking two students to come up to the front of the class and draw two waveforms: half-wave and full-wave, along with their original AC (unrectified) waveforms.
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Question 26 of 31
Calculate the approximate DC output voltage of this power supply when it is not loaded:
Reveal answerVout ≈ 21.4 volts
Notes:Ask your students to explain how they solved for this output voltage, step by step.
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Question 27 of 31
Calculate the approximate DC output voltage of this power supply when it is not loaded:
Reveal answerVout ≈ 11.6 volts
Notes:Ask your students to explain how they solved for this output voltage, step by step.
i m using power supply for CCTV PTZ Camera with his adaptor rating of 230v AC input & 24V AC Output ,2A load current. what would be the power consumption is their from the main supply line? means is it taking 2 amp from main line of it would be from the adaptor itself?