*Question E9E08:
What is a use for a Wilkinson divider?*  

*Correct Answer is  C: To divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance*  

### AI Response: (may contain errors)  

The correct answer to the question about the use of a Wilkinson divider is:

**C: To divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance.**

### Explanation of the Correct Answer:
- A Wilkinson power divider is designed to split an input signal into two equal output signals while ensuring that the input impedance remains constant (in this case, 50 ohms). 
- This is achieved through a combination of resistive and reactive components that allow for equal power distribution without introducing significant loss or reflection.

### Why the Other Choices are Incorrect:
- **A: To divide the operating frequency of a transmitter signal so it can be used on a lower frequency band.**
  - This is incorrect because a Wilkinson divider does not change the frequency of the signal; it only divides the power of the signal.

- **B: To feed high-impedance antennas from a low-impedance source.**
  - This is incorrect because a Wilkinson divider is specifically designed for matching 50-ohm systems. It does not convert low impedance to high impedance.

- **D: To divide the frequency of the input to a counter to increase its frequency range.**
  - This is incorrect because a Wilkinson divider does not operate by dividing frequency; it divides power. Frequency division is typically done using flip-flops or other digital circuits.

### Useful Formulas and Rules of Thumb:
- The power division in a Wilkinson divider is ideally equal, meaning each output receives half of the input power. If the input power is $P_{in}$, then:
  
  $$P_{out1} = P_{out2} = \frac{P_{in}}{2}$$

- The input impedance remains at 50 ohms, which is crucial for maintaining system performance and minimizing reflections.

This understanding of the Wilkinson divider is essential for the Extra Class exam, as it highlights both its function and the importance of impedance matching in RF systems.