Question

Match the LIST-I with LIST-II

LIST-I (Configuration of Bipolar Transistors)		LIST-II (Characteristics)
A.	Common Base	I.	Current Gain but no Voltage Gain
B.	Common Emitter	III.	Both Current and Voltage Gain
C.	Common Collector	II.	Voltage Gain but no Current Gain

Choose the correct answer from the options given below:

• A. A - I, B - II, C - III
• B. A - II, B - III, C - I
• C. A - I, B - III, C - II
• D. A - III, B - II, C - I

Hint:

A simple way to remember BJT configurations: - **Common Emitter (CE):** The all-rounder. Good voltage and current gain. Inverts the signal. - **Common Collector (CC):** The "buffer". High current gain, unity voltage gain. Used for impedance matching. - **Common Base (CB):** The "current follower". Unity current gain, high voltage gain. Used for high-frequency applications.

Answer 1

The Correct Option is B

Step 1: Analyze the characteristics of each BJT configuration. - A. Common Base (CB): This configuration has a low input impedance and high output impedance. Its current gain (\(\alpha\)) is slightly less than 1. However, it can have a very high voltage gain. Therefore, it provides "Voltage Gain but no Current Gain" (since the gain is less than unity). This matches II. - B. Common Emitter (CE): This is the most widely used configuration. It has a medium input and output impedance. It provides significant gain for both current (\(\beta\)) and voltage. Therefore, it provides "Both Current and Voltage Gain". This matches III. - C. Common Collector (CC): Also known as an emitter follower, this configuration has a high input impedance and low output impedance. Its voltage gain is approximately 1 (unity). It has a high current gain (\(\beta+1\)). Therefore, it provides "Current Gain but no Voltage Gain". This matches I.
Step 2: Formulate the correct matching sequence. Based on the analysis: - A \(\rightarrow\) II - B \(\rightarrow\) III - C \(\rightarrow\) I This sequence corresponds to option (2).