*Question G7A02:
Which of the following components are used in a power supply filter network?*  

*Correct Answer is  C: Capacitors and inductors*  

### AI Response: (may contain errors)  

In a power supply filter network, the primary goal is to smooth out the rectified AC voltage to produce a steady DC output. The components used to achieve this are:

- **Capacitors**: These store and release energy, helping to smooth out voltage fluctuations by filling in the gaps between the peaks of the rectified AC waveform.
- **Inductors**: These resist changes in current, further smoothing the output by reducing the ripple in the DC voltage.

Thus, the correct answer is **C: Capacitors and inductors**.

### Why the Correct Answer is Correct:
- **Capacitors** and **inductors** work together in a filter network to reduce the ripple voltage and provide a more constant DC output. Capacitors smooth the voltage, while inductors smooth the current.

### Why the Other Choices are Incorrect:
- **A: Diodes**: While diodes are crucial in converting AC to DC in a rectifier circuit, they are not used in the filtering stage.
- **B: Transformers and transducers**: Transformers are used to step up or step down AC voltage levels, and transducers convert one form of energy to another. Neither is used in the filtering process.
- **D: All these choices are correct**: This is incorrect because not all listed components are used in the filter network.

### Useful Formulas or Rules of Thumb:
- The effectiveness of a capacitor in reducing ripple is often given by the formula:
  $$ V_{\text{ripple}} = \frac{I}{f \cdot C} $$
  where:
  - $V_{\text{ripple}}$ is the ripple voltage.
  - $I$ is the load current.
  - $f$ is the frequency of the rectified AC (usually twice the AC line frequency for full-wave rectification).
  - $C$ is the capacitance.

Understanding the role of capacitors and inductors in a filter network is key to ensuring a stable DC output in power supplies.