Test: Characteristics of Amplifiers - Electronics and Communication Engineering (ECE) MCQ

The state at which amplifier has zero input signal is called zero signal condition, Non-signal condition, quiescent condition. There anything named empty-signal condition.

The quiescent point is the operating point of an amplifier where the DC condition of amplifier is constant. For that we have to make sure that DC collector-emitter voltage, DC collector current, DC base current are constant.

R₁, R₂, R_C are, used to bias the circuit while R_L is used as a load resistor. R₁, R₂ are used as a voltage divider. R_C is used to control collector current.

The basic function of biasing is to maintain amplifier in quiescent condition. The amplifier will properly work only if the quiescent condition is stable.

 The input capacitance as its name indicates, used to prevent DC offset voltages in the input. It also prevents the transistor bias voltage to fed back to input generating circuit.

The major function of emitter bypass capacitance is to increase gain. Since it provides a low reactive path to the AC signal without changing the quiescent point.

The emitter bypass capacitor is not meant for reducing loading effect of emitter resistance. It is to increase gain. It provides a low reactive path to the AC signal without changing the quiescent point.

Early effect is the increase in the collector current without increase in input due to heating of semiconductor material which in turn reduce the resistance thus increases current. The emitter resistor decreases effective input voltage decrease when collector current increases and thus it reduces collector current itself.

The output capacitor or output coupling capacitor is provided to pass AC signal and to block DC signal. It also helps to couple the amplifier to load or next amplifier.

Voltage divider bias is more stable because the biased voltage will not change. It is best to use voltage divider bias for accuracy.