MCQs on BJT Biasing Circuits - I

What is the Q-point in a transistor biasing circuit?

• The maximum voltage across collector-emitter terminals

• The minimum base current required for conduction

• The fixed point representing the DC operating condition

• The cutoff threshold of a transistor

For a BJT to operate in the active region, which of the following is true?

• Both junctions are reverse biased

• Base-emitter is forward biased and base-collector is reverse biased

• Both junctions are forward biased

• Base-collector is forward biased and base-emitter is reverse biased

In a fixed bias configuration, how is the base current I_B calculated?

• I_B = (V_CC - V_BE)/R_C

• I_B = V_CE / R_B

• I_B = (V_CC - V_BE)/R_B

• I_B = V_BE / R_B

What is the main drawback of a fixed bias circuit?

• Low gain

• Poor thermal stability

• Complexity in design

• High input resistance

In fixed bias with emitter resistor, why is R_E added?

• To increase input impedance

• To improve voltage gain

• To improve thermal stability

• To increase base current

What happens to the load line when R_C increases in a fixed bias circuit?

• It remains unchanged

• It becomes steeper

• It becomes flatter

• It shifts upward

What is the base current equation in a fixed bias with emitter resistor circuit?

• I_B = (V_CC - V_BE)/(R_B + R_E)

• I_B = (V_CC - V_BE)/(R_B + (1 + β) R_E)

• I_B = V_BE / R_B

• I_B = V_CC / R_B

Which region of operation is characterized by both junctions being forward biased?

• Cut-off

• Active

• Reverse-active

• Saturation

The collector current in fixed bias is related to base current by which expression?

• I_C = α I_E

• I_C = I_B / β

• I_C = β I_B

• I_C = β² I_B

What is the typical forward voltage drop of a silicon BJT base-emitter junction?

• 1.2 V

• 0.3 V

• 0.6 to 0.7 V

• 2 V