*Question T6A09:
What electrical component is used to protect other circuit components from current overloads?*  

*Correct Answer is  A: Fuse*  

### AI Response: (may contain errors)  

To protect other circuit components from current overloads, the correct answer is:

**A: Fuse**

### Explanation of the Correct Answer:
- A **fuse** is a safety device that interrupts the flow of current when it exceeds a certain level. It contains a metal wire or strip that melts when too much current flows through it, breaking the circuit and preventing damage to other components.

### Why the Other Choices are Incorrect:
- **B: Thyratron**  
  A thyratron is a type of gas-filled tube used for switching and controlling high voltages and currents, but it does not provide overload protection. It is primarily used in applications like pulse modulation and high-power switching.

- **C: Varactor**  
  A varactor (or varicap) is a type of diode that acts as a variable capacitor, primarily used in tuning circuits. It does not serve any protective function against current overloads.

- **D: All these choices are correct**  
  This option is incorrect because only the fuse is designed to protect against current overloads. The other components do not fulfill this role.

### Summary:
- A fuse is essential for protecting circuits from excessive current, while thyratrons and varactors serve different purposes in electronic circuits. Always remember that fuses are a fundamental safety component in electrical systems.