196. For above question I_E is—

1. 1. 1 pA

   
   
   

   2. 2 pA

   
   
   

   3. 3 pA

   
   
   

   4. 50 pA

   
   
   

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1. View Hint View Answer Discuss in Forum

   I_E ≈ I_C ≈ 1 pA.

   Correct Option: A

   I_E ≈ I_C ≈ 1 pA.

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197. When determining the common-emitter current gain by making small changes in direct currents, the collector voltage is held constant so that—

1. 1. The output resistance will be high

   
   
   

   2. The transistor will not burn out

   
   
   

   3. The change in emitter current will be due to a change in collector current

   
   
   

   4. The change in collector current will be due to a change in base current

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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198. The most noticeable effect of a small increase in temperature in the common emitter connected transistor is—

1. 1. The increase in the ac current gain

   
   
   

   2. The decrease in the ac current gain

   
   
   

   3. The increase in output resistance

   
   
   

   4. The increase in I_CEO
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   Since the leakage current is most sensitive to temperature among the given parameters.

   Correct Option: D

   Since the leakage current is most sensitive to temperature among the given parameters.

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199. α cut-off frequency of a bipolar junction transistor increases with the—

1. 1. Increase in base width

   
   
   

   2. Increase in emitter width

   
   
   

   3. Increase in the collector width

   
   
   

   4. Decrease in the base width

   
   
   

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1. View Hint View Answer Discuss in Forum

   We know that,
   

   fα = fT = hfe.	1	…(1)
   	2πRC

   
   Where, f_α = cut-off frequency of a BJT
   h_fe = Gain factor
   Capacitance C is given by
   

   C =	∈0A	…(2)
   	d

   
   Where,
   ε_e = Free space permittivity
   C = Capacitance.
   A = Area
   d = Depletion width
   From the relation (2) it is clear that with increase in base width C decreases which increases the f_α i.e. α- cut off frequency.
   Hence alternative (A) is the correct choice

   Correct Option: A

   We know that,
   

   fα = fT = hfe.	1	…(1)
   	2πRC

   
   Where, f_α = cut-off frequency of a BJT
   h_fe = Gain factor
   Capacitance C is given by
   

   C =	∈0A	…(2)
   	d

   
   Where,
   ε_e = Free space permittivity
   C = Capacitance.
   A = Area
   d = Depletion width
   From the relation (2) it is clear that with increase in base width C decreases which increases the f_α i.e. α- cut off frequency.
   Hence alternative (A) is the correct choice

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200. The beta (β) of a transistor may be determined directly from the plots of—

1. 1. V_CB versus i_C for constant values of I_E

   
   
   

   2. V_BC versus i_E for constant values of I_B

   
   
   

   3. V_CE versus i_C for constant values of I_B

   
   
   

   4. V_BE versus i_B for constant values of v_CE
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   The gain of transistor i.e. β may be determined directly from the V_CE versus I_C plot for constant values of I_B.

   Correct Option: C

   The gain of transistor i.e. β may be determined directly from the V_CE versus I_C plot for constant values of I_B.

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