*Question G7A04:
What is characteristic of a half-wave rectifier in a power supply?*  

*Correct Answer is  A: Only one diode is required*  

### AI Response: (may contain errors)  

The correct answer to the question about the characteristic of a half-wave rectifier is:

**A: Only one diode is required.**

### Explanation of the Correct Answer:
- A half-wave rectifier uses only one diode to convert AC (alternating current) to DC (direct current). This diode allows current to pass through only during one half of the AC cycle, effectively blocking the other half. This simplicity is a key characteristic of half-wave rectifiers.

### Explanation of the Incorrect Answers:
- **B: The ripple frequency is twice that of a full-wave rectifier.**
  - This statement is incorrect. In fact, the ripple frequency of a half-wave rectifier is the same as the input frequency. For a full-wave rectifier, the ripple frequency is twice that of the input frequency because it rectifies both halves of the AC cycle.

- **C: More current can be drawn from the half-wave rectifier.**
  - This is also incorrect. A half-wave rectifier typically allows less current to be drawn compared to a full-wave rectifier because it only utilizes one half of the input waveform, leading to lower average output current.

- **D: The output voltage is two times the peak input voltage.**
  - This statement is incorrect as well. The output voltage of a half-wave rectifier is approximately equal to the peak input voltage minus the forward voltage drop of the diode. It does not double the peak input voltage.

### Useful Formulas:
- The average output voltage ($V_{avg}$) of a half-wave rectifier can be approximated by:
  
  $$V_{avg} = \frac{V_{peak}}{\pi}$$

  where $V_{peak}$ is the peak voltage of the AC input.

- The ripple voltage ($V_{ripple}$) can be calculated, but it is important to note that the ripple frequency for a half-wave rectifier is the same as the input frequency ($f_{input}$), while for a full-wave rectifier, it is $2 \times f_{input}$.

This information should help clarify the characteristics of half-wave rectifiers and prepare you for the exam.