*Question E5A05:
What is the result of increasing the Q of an impedance-matching circuit?*  

*Correct Answer is  A: Matching bandwidth is decreased*  

### AI Response: (may contain errors)  

Increasing the Q (quality factor) of an impedance-matching circuit affects its performance in specific ways. 

### Correct Answer: A - Matching bandwidth is decreased

1. **Why the correct answer is correct:**
   - The Q factor is a measure of how selective a circuit is at its resonant frequency. A higher Q indicates a narrower bandwidth. This means that as the Q increases, the circuit becomes more selective, allowing it to match impedance very well at a specific frequency but reducing the range of frequencies over which it can effectively match. 
   - The relationship can be expressed as:
   $$ BW = \frac{f_0}{Q} $$
   where:
   - $BW$ = bandwidth
   - $f_0$ = resonant frequency
   - $Q$ = quality factor

   As $Q$ increases, $BW$ decreases.

### Why the other choices are incorrect:

2. **B: Matching bandwidth is increased**
   - This is incorrect because increasing the Q factor results in a narrower bandwidth, not a wider one. A lower Q would increase the bandwidth.

3. **C: Losses increase**
   - This is also incorrect. While higher Q circuits can have higher losses due to increased selectivity, the statement does not universally hold true. In fact, a well-designed high-Q circuit can minimize losses at resonance.

4. **D: Harmonics increase**
   - This choice is incorrect as well. The Q factor does not directly influence the generation of harmonics. Harmonics are more related to the non-linearities in the circuit rather than the Q factor itself.

### Summary:
- Increasing the Q of an impedance-matching circuit decreases the matching bandwidth, making it more selective at a specific frequency. Understanding this relationship is crucial for effective circuit design and operation in amateur radio applications.