The output frequency of a full-wave rectifier is twice that of the input frequency due to its unique operational principle. A full-wave rectifier, specifically the bridge rectifier configuration, rectifies both halves of the AC input cycle, resulting in a more continuous and pulsating DC output.
In a full-wave rectifier, the input AC waveform consists of two half-cycles: the positive half-cycle and the negative half-cycle. Unlike a half-wave rectifier that only utilizes one half-cycle, a full-wave rectifier takes advantage of both. Here’s how the process unfolds:
- Positive Half-Cycle: During the positive half-cycle of the input AC signal, the upper diode conducts, allowing current to flow through the load resistor in one direction. Simultaneously, the lower diode is in a reverse-biased state and does not conduct.
- Negative Half-Cycle: As the AC signal transitions to the negative half-cycle, the lower diode becomes forward-biased, conducting current in the opposite direction through the load resistor. Meanwhile, the upper diode is in a reverse-biased state.
By rectifying both halves of the input cycle, the full-wave rectifier effectively doubles the frequency of the output waveform. Each half-cycle of the input contributes to the output, resulting in a smoother DC signal with less ripple.
This doubling of frequency has practical advantages. For instance, it allows for the reduction of filter capacitor size in the smoothing stage since the pulsating DC output has a higher frequency, making it easier to filter and resulting in a more stable DC voltage for various electronic applications. In summary, the full-wave rectifier’s ability to utilize both halves of the input AC cycle contributes to its doubled output frequency compared to the input frequency.