*Question E7H08:
Which of the following components can be used to reduce thermal drift in crystal oscillators?*  

*Correct Answer is  A: NP0 capacitors*  

### AI Response: (may contain errors)  

To reduce thermal drift in crystal oscillators, the correct choice is:

**A: NP0 capacitors**

### Explanation:

1. **Why NP0 capacitors are correct:**
   - **NP0 capacitors** are a type of ceramic capacitor known for their stable capacitance over a wide temperature range. The "NP0" designation indicates a temperature coefficient of 0 parts per million per degree Celsius (0 ppm/°C), meaning they do not change capacitance with temperature. This stability helps maintain the frequency stability of crystal oscillators, which is crucial for reducing thermal drift.

2. **Why the other choices are incorrect:**
   - **B: Toroidal inductors**  
     Toroidal inductors are used for their low electromagnetic interference and efficient magnetic field containment, but they do not inherently stabilize frequency over temperature changes in crystal oscillators.
   
   - **C: Wirewound resistors**  
     Wirewound resistors are known for their precision and power handling but can have significant inductance and are not designed to stabilize frequency over temperature changes.
   
   - **D: Non-inductive resistors**  
     Non-inductive resistors are designed to minimize inductance, which is useful in high-frequency applications, but they do not address frequency stability over temperature changes in crystal oscillators.

### Useful Rule of Thumb:

- **Temperature Coefficient:**  
  For components used in frequency-sensitive applications like crystal oscillators, a low or zero temperature coefficient (like NP0) is desirable to minimize frequency drift due to temperature changes.