*Question E7B11:
In Figure E7-1, what is the purpose of R3?*  

*Correct Answer is  D: Self bias*  

### AI Response: (may contain errors)  

In the context of the circuit shown in Figure E7-1, let's analyze the purpose of resistor R3.

### Correct Answer: D - Self bias

**Explanation:**
- R3 is used for self-biasing the transistor. Self-biasing helps stabilize the operating point of the transistor against variations in temperature and transistor parameters. It achieves this by providing a feedback mechanism that adjusts the biasing based on the transistor's own characteristics.

### Why the Other Choices are Incorrect:

- **A: Fixed bias**
  - Fixed bias typically involves a resistor connected directly to a fixed voltage source, which does not provide the feedback mechanism that R3 does. R3's role is to adjust the bias dynamically based on the transistor's operation.

- **B: Emitter bypass**
  - An emitter bypass capacitor is used to increase the gain of the amplifier by providing a low impedance path to ground for AC signals, effectively bypassing the emitter resistor for AC. R3 does not serve this purpose; it is not bypassing anything but rather providing biasing.

- **C: Output load resistor**
  - An output load resistor is used to provide a load for the output stage of the amplifier. R3 is not functioning as a load resistor; it is part of the biasing network.

### Summary:
- R3 is essential for self-biasing, ensuring stable operation of the transistor.
- The other options do not accurately describe the function of R3 in the circuit.

This understanding of biasing is crucial for designing stable amplifier circuits and is a key concept in the Extra Class exam.