In a common emitter amplifier circuit using n-p-n transistor, the phase difference between the input and output voltage will be:

• A. 180°
• B. 45°
• C. 90°
• D. 135°

In a common emitter amplifier circuit that utilizes an n-p-n transistor, the relationship between the input and output voltages is characterized by a specific phase shift. When the input signal is applied to the base of the transistor, the output signal taken from the collector is inverted. This means that when the input voltage increases, the output voltage decreases, and vice versa.

Phase Difference

The phase difference between the input and output voltage in this configuration is:

• A. 180° - This is the correct answer.
• B. 45°
• C. 90°
• D. 135°

Thus, the correct choice is A. 180°. This inversion is a key feature of the common emitter amplifier, making it useful in various applications where signal amplification is needed.