Full wave rectification using CTT and amplitude of output waveform

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Discussion Overview

The discussion revolves around the experiment of full wave rectification using a center tap transformer, focusing on the output waveform's amplitude and the interpretation of voltage readings. Participants explore the relationship between RMS and peak voltages, the effect of a capacitor on the output, and the application of formulas related to ripple factor.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant notes that the transformer outputs 12V RMS, while the peak voltage observed is 18V, questioning the expected amplitude of the output waveform.
  • Another participant explains the relationship between RMS and peak voltage, suggesting that the RMS value is approximately equal to the peak voltage divided by the square root of 2.
  • A participant asserts that while the capacitor smoothes the waveform, it does not reduce the maximum voltage, which remains at 18V.
  • One participant expresses confusion about the ripple factor formula used, suggesting that the instructor may have provided an incorrect formula, referencing a different interpretation found on Wikipedia.

Areas of Agreement / Disagreement

Participants generally agree on the relationship between RMS and peak voltage, but there is disagreement regarding the effect of the capacitor on the output waveform and the correct formula for ripple factor.

Contextual Notes

The discussion includes assumptions about the definitions of RMS and peak voltage, as well as the application of formulas related to ripple factor, which may not be universally accepted or understood among participants.

Who May Find This Useful

Readers interested in electrical engineering, specifically in rectification processes, waveform analysis, and the application of related mathematical concepts.

PainterGuy
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Hello, :smile:

I did an experiment on full wave rectification using center tap transformer. The transformer read: Input 220V, Output 12V, 12V. I used two diodes and 1 micro farad capacitor. As you see capacitor's capacitance is very little so it didn't effect the overall output because I checked the output without using it. The peaks had amplitude of 18V. Shouldn't it be 12V or less? I connected oscilloscope across the resistor. Have a see on the the given diagram:

http://img233.imageshack.us/img233/4901/cttfullwaverectificatio.jpg

Help me out with this. Much grateful.

Cheers
 
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mdjensen22 said:
The capacitor will pull it down some as it smoothes the waveform
No it won't. The maximum value will stay 18 volts, it just won't dip all the way down to 0 in between alternations.
 
You are correct. Not sure where my head was on that one...Sorry for the confusion.
 
Many thanks, mdjensen22 and Jiggy-Ninja.:wink:

That means the value of the voltage given on the transformer label was RMS.

I used the formula, ripple factor=IL/FC. IL was almost 12.09 mA. I used the value of F as 60 Hz which was the frequency of AC source and the voltage of AC was 220V.

I think the instructor gave us the wrong formula because here on Wikipedia it seems Wiki is saying something different:
http://en.wikipedia.org/wiki/Ripple_(electrical)#Time-domain_ripple

Could you help me out with this please? Much grateful.

Cheers
 

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