NEIEP Mechanics Practice Exam

What method is used to reduce ripple voltage from a full wave rectifier?

1. Add capacitors and inductors after the rectifier diodes

2. Increase the frequency of input AC

3. Use transformer isolation

4. Add resistors in series with the output

The correct answer is: Add capacitors and inductors after the rectifier diodes

To reduce ripple voltage from a full wave rectifier, the standard and effective method involves the use of capacitors and inductors after the rectifier diodes. When a full wave rectifier converts AC to DC, the output is not a smooth DC voltage but rather a pulsating waveform, known as ripple voltage. Adding capacitors helps to smooth out these fluctuations by charging during the peak voltage and discharging when the voltage drops, thus providing a more steady voltage level. The capacitors store electrical energy and release it to fill in the gaps of voltage drop between the peaks of the pulsating output, effectively reducing the amplitude of the ripple. Inductors can also be used in conjunction with capacitors to further smooth the output. Inductors resist changes in current, which can help to dampen the variations in the voltage output. The combination of these components effectively lowers the ripple voltage, leading to a cleaner DC output. While increasing the frequency of the input AC may influence the behavior of the rectification process, it does not directly reduce ripple voltage effectively. Transformer isolation does not impact ripple voltage reduction, and adding resistors in series with the output typically increases voltage drop and can lead to more ripple by creating additional losses, rather than helping