With the aid of well-labelled diagrams outline in details the THREE possibleconditions for an amplifier [12 marks](b) With the aid of a well-labelled diagram show how the conditions in (a) are achievedfor a common-emitter amplifier. [10 marks]2. With the aid of well-labelled diagrams demonstrate how a silicon bipolar transistorresponds to an ac input signal in(a) Linear operation [ 6 marks](b) Nonlinear operation [12 marks]

1a. The three possible conditions for an amplifier are:

i. Active Region: In this region, the transistor amplifies the signal. The input signal is applied to the base-emitter junction, and the output is taken from the collector-emitter junction. The base-emitter junction is forward biased, and the collector-emitter junction is reverse biased.

ii. Cut-off Region: In this region, both the base-emitter and collector-emitter junctions are reverse biased. The transistor is in the OFF state and does not conduct. This condition is used in switch operations.

iii. Saturation Region: In this region, both the base-emitter and collector-emitter junctions are forward biased. The transistor is in the ON state and conducts maximum current. This condition is also used in switch operations.

1b. A common-emitter amplifier achieves these conditions as follows:

The input signal is applied to the base-emitter junction, and the output is taken from the collector-emitter junction. By varying the biasing conditions, we can operate the transistor in the active, cut-off, or saturation regions.

2a. Linear Operation of a Silicon Bipolar Transistor:

In the linear operation, the transistor operates in the active region. The input signal is applied to the base-emitter junction, and the output is taken from the collector-emitter junction. The output signal is an amplified version of the input signal.

2b. Nonlinear Operation of a Silicon Bipolar Transistor:

In the nonlinear operation, the transistor operates in the cut-off or saturation regions. In the cut-off region, the transistor is in the OFF state and does not conduct. In the saturation region, the transistor is in the ON state and conducts maximum current. The output signal is not a linear function of the input signal.