Question

Which of the following is NOT an advantage of full wave rectifiers?
1. Full wave rectifiers have higher rectifying efficiency than half-wave rectifiers. This means that they convert AC to DC more efficiently. 
2. The output voltage of centre-tapped full wave rectifier has lower ripples than a halfwave rectifier.  
3. They have low power loss because no voltage signal is wasted in the rectification process.
4. The centre-tapped rectifier is more expensive than a half-wave rectifier and tends to occupy a lot of space

Answer 1

Correct Answer - Option 4 : The centre-tapped rectifier is more expensive than a half-wave rectifier and tends to occupy a lot of space

Explanation:

A full-wave rectifier converts both the cycles of AC input to DC output whereas a half-wave rectifier converts only the positive cycle of the AC input to DC output.

Full-wave rectifiers have several advantages over half-wave rectifiers.

These advantages are mentioned below:

1) The rectification efficiency of a full-wave rectifier is double that of the half-wave rectifier because it converts both the cycles of AC to DC.

2) Ripple factor is less in full-wave rectifier so waveform is smooth.

3) The ripple frequency is also double so they are easy to filter out.

4) The full-wave rectifier produces high DC output voltage and current so the output power is higher.

5) The full-wave rectifier has a better transformer utilization factor.

In a Full Wave Rectifier circuit, two diodes are now used, one for each half of the cycle. A multiple winding transformer is used whose secondary winding is split equally into two halves with a common centre-tapped connection.

Hence the center-tapped rectifier is more expensive than a half-wave rectifier and tends to occupy a lot of space.

So option (4) is the correct answer.