*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 bandwidth and efficiency. Here's how:

1. **Correct Answer: Matching bandwidth is decreased**

   - The quality factor, $Q$, is defined as the ratio of the resonant frequency, $f_0$, to the bandwidth, $BW$:  
     $$Q = \frac{f_0}{BW}$$  
   - A higher $Q$ means a narrower bandwidth because the circuit becomes more selective. It can only effectively match impedances over a smaller range of frequencies.

2. **Why the other choices are incorrect:**

   - **B: Matching bandwidth is increased**  
     - This is incorrect because increasing $Q$ actually decreases the bandwidth, as shown in the formula above.

   - **C: Losses increase**  
     - Generally, a higher $Q$ indicates lower losses in the circuit. A high $Q$ circuit is more efficient at storing energy, which means less energy is lost as heat.

   - **D: Harmonics increase**  
     - The $Q$ factor primarily affects bandwidth and selectivity, not the generation of harmonics. Harmonics are more related to the non-linear behavior of components, not the $Q$ of the circuit.

Understanding the relationship between $Q$ and bandwidth is crucial for designing circuits that need to operate efficiently over a specific range of frequencies.