In a Bipolar junction transistor, the largest current flows though

Options

A. in the emitter
B. in the collector
C. in the base
D. through CB junction

Answer

To solve the question, "In a Bipolar Junction Transistor, the largest current flows through," we need to analyze the structure and functioning of a Bipolar Junction Transistor (BJT).

### Step-by-Step Solution:

1. **Understanding the Structure of BJT**:
A Bipolar Junction Transistor consists of three regions: the Emitter (E), the Base (B), and the Collector (C). The emitter is heavily doped, the base is lightly doped, and the collector is moderately doped.

**Hint**: Remember the arrangement of the three regions: Emitter, Base, and Collector.

2. **Current Flow in BJT**:
- The three main currents in a BJT are:
- Emitter Current (IE)
- Base Current (IB)
- Collector Current (IC)

**Hint**: Identify the three types of currents and their respective roles in the operation of the transistor.

3. **Current Relationships**:
- The emitter current (IE) is the sum of the base current (IB) and the collector current (IC):
\[ I_E = I_B + I_C \]
- The collector current (IC) is related to the emitter current (IE) by the current gain (α):
\[ I_C = \alpha I_E \]
- Here, α (alpha) is typically around 0.95, meaning that about 95% of the emitter current contributes to the collector current.

**Hint**: Recall the relationship between the emitter, base, and collector currents.

4. **Comparing the Currents**:
- Since α is less than 1, it indicates that not all of the emitter current flows into the collector. The base current (IB) is much smaller than both the emitter and collector currents.
- Therefore, the largest current in the BJT is the emitter current (IE), followed by the collector current (IC), and the smallest is the base current (IB).

**Hint**: Compare the magnitudes of IE, IC, and IB to determine which is the largest.

5. **Conclusion**:
- Based on the analysis, the largest current in a Bipolar Junction Transistor flows through the emitter (IE).

**Final Answer**: The largest current flows through the Emitter (IE).