Question

Ripple frequency of a full wave rectifier is

Hint:

Compare rectifiers:
- Half-wave rectifier: Output has one pulse per input cycle $\implies f_{\text{ripple}} = f_{\text{in}}$.
- Full-wave rectifier: Output has two pulses per input cycle $\implies f_{\text{ripple}} = 2f_{\text{in}}$.

Answer 1

Step 1: Understanding the Concept:
A rectifier converts alternating current (AC) to direct current (DC). The output is not perfectly smooth DC but contains fluctuations called ripples. The frequency of these ripples depends on the type of rectifier used.

Step 2: Key Formula or Approach:
Understand the operation waveform of a full-wave rectifier. It "flips" the negative half-cycles of the input AC sine wave into positive half-cycles.

Step 3: Detailed Explanation:
Let the input AC signal have a frequency $f_{\text{in}}$. This means it completes one full cycle (one positive half and one negative half) in time $T = 1/f_{\text{in}}$.
A full-wave rectifier conducts current during both half-cycles. The output waveform consists of a series of positive pulses.
For every single full cycle of the input AC, the full-wave rectifier produces two identical positive output pulses.
Therefore, the fundamental frequency of the repeating pattern in the output (the ripple frequency) is twice the frequency of the input signal.
\[ f_{\text{ripple}} = 2 \times f_{\text{in}} \]
For example, if the standard mains supply frequency is 50 Hz, the ripple frequency from a full-wave rectifier will be 100 Hz.

Step 4: Final Answer:
The ripple frequency is $2f_{\text{in}}$.