Analysing a Filter Rectifier Circuit: Solve for VDC, Vr and Ripple %

In summary, the conversation is about a beginner in Electronics Engineering who is analyzing a filter rectifier circuit. They have been given questions and solutions by their professor, but the numbers for the full wave analysis are not matching up. The analysis requires them to find VDC, Vr, and ripple % using specific formulas. The person has found correct answers for the half wave filter, but not for the full wave. It is mentioned that the frequency for a half wave rectifier is 60Hz, while for a full wave it is 120Hz. After realizing they were using the wrong value for period, the person was able to find the correct answers.
  • #1
pooface
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0
Hello I'm a beginner (Second Semester) at Electronics Engineering.

In the attachment is the image of the filter rectifier circuit that I am analyzing. My professor has given us questions and their solutions but for my full wave filter rectifier analysis the numbers are not the same.

The analysis asks me three questions:

VDC, Vr, and ripple %

Formulas I use:

Vrp-p=(VLpeak/RL * period) / C (capacitor value).

VDC = VLpeak - Vrpeaktopeak/2

Vr(rms)=.577* Vrp-p/2

r=Vr(rms)/VDC

My halfwave filter answers are correct and these are the formulas I used.
But my fullwave/bridge answers go wrong. someone please do this question and see what answer they get.
 

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  • #2
A half wave and full wave rectifier differ in certain ways. You can't apply all formulas (or same value for period) to both. What value are you using for period, T?

Vrpp = (Vpin * T)/RC

Please so your exact calculations, like for example how you got Vrrms
 
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  • #3
Have to remember, in a half wave rectifier the frequency is 60 hz as it chops off the bottom half of each cycle. In a full wave circuit, it translates the bottom cycle to the top to give 120hz peaks.
 
  • #4
ranger said:
A half wave and full wave rectifier differ in certain ways. You can't apply all formulas (or same value for period) to both. What value are you using for period, T?

Vrpp = (Vpin * T)/RC

Please so your exact calculations, like for example how you got Vrrms
EDIT:

Nevermind thanks so much ! i got it. You were right. I was using the wrong T value. Fullwave is 120Hz so i should be using 1/120hz for T.

The numbers add up now. Thanks so much.
 
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FAQ: Analysing a Filter Rectifier Circuit: Solve for VDC, Vr and Ripple %

1. What is a filter rectifier circuit?

A filter rectifier circuit is an electronic circuit that converts alternating current (AC) into direct current (DC) by using a combination of diodes and capacitors. It is used to remove the unwanted alternating component from the rectified output, resulting in a smoother DC output.

2. How do I calculate VDC, Vr, and Ripple % in a filter rectifier circuit?

To calculate VDC (DC output voltage), you can use the formula VDC = Vrms - Vf, where Vrms is the root mean square value of the AC input voltage and Vf is the voltage drop across the diode. Vr (ripple voltage) can be calculated using the formula Vr = VDC x Ripple %, where Ripple % is the percentage of the peak-to-peak ripple voltage. To find the Ripple %, you can use the formula Ripple % = Vr / VDC x 100.

3. What is the purpose of a filter in a rectifier circuit?

The primary purpose of a filter in a rectifier circuit is to smooth out the pulsating DC output, resulting in a more constant DC voltage. This is done by removing the AC component and reducing the ripple voltage.

4. How does the type of filter affect the performance of a rectifier circuit?

The type of filter used in a rectifier circuit can affect its performance in terms of output voltage, ripple voltage, and efficiency. A larger filter capacitor will result in a lower ripple voltage and higher efficiency, while a smaller capacitor will result in a higher ripple voltage and lower efficiency. The type of filter (i.e. passive or active) will also affect the performance, with an active filter providing better filtering and lower ripple voltage compared to a passive filter.

5. What are the common applications of filter rectifier circuits?

Filter rectifier circuits are commonly used in power supplies for electronic devices, battery chargers, and motor control circuits. They are also used in various industrial and commercial applications where a stable DC voltage is required.

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