306. Find A_v
     
     
     

1. 1. – 10

   
   
   

   2. 10

   
   
   

   3. – 11

   
   
   

   4. 11

   
   
   

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   Vo = –	400	. Vi
   	40

   
   

   or =	V0	= – 10
   	Vi

   
   or A_v = – 10

   
   

   Correct Option: A

   Vo = –	400	. Vi
   	40

   
   

   or =	V0	= – 10
   	Vi

   
   or A_v = – 10

   
   

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307. In a differential amplifier, CMRR can be improved by using an increased:

1. 1. emitter resistance

   
   
   

   2. collector resistance

   
   
   

   3. power supply voltages

   
   
   

   4. source resistance

   
   
   

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   NA

   Correct Option: A

   NA

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308. The dissipation at the collector is zero in the quiescent state and increases with excitation in the case of:

1. 1. Class A series-fed amplifier

   
   
   

   2. Class A transformer coupled amplifier

   
   
   

   3. Class AB amplifier

   
   
   

   4. Class B amplifier

   
   
   

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   NA

   Correct Option: A

   NA

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309. The change in the value of the emitter resistance R_E in a difference amplifier:

1. 1. affects the difference mode gain, A_d

   
   
   

   2. affects the common mode gain, A_c

   
   
   

   3. affects both A_d and A_c

   
   
   

   4. does not affect either A_d and A_c

   
   
   

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   ACM =	–hfe · Rc
   	hie + Rs + (1 + hfe)RE

   
   

   and ADM =	1	×	–hfe·Rc
   	2		(Rs + hie)

   
   Hence alternative (B) is the correct choice.

   Correct Option: B

   ACM =	–hfe · Rc
   	hie + Rs + (1 + hfe)RE

   
   

   and ADM =	1	×	–hfe·Rc
   	2		(Rs + hie)

   
   Hence alternative (B) is the correct choice.

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310. A op-amp has an offset voltage of 1 mv and is ideal in all respects. If this op-amp is used in the circuit shown below the output voltage will be (select the nearest value)
     
     
     

1. 1. 1 mV

   
   
   

   2. 1 V

   
   
   

   3. ± 1 V

   
   
   

   4. 0 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   Output of the op-amp due to offset voltage of 1 mV
   

   Vo = –		1 MΩ		Vi
   		1 kΩ

   
   or V_o = – (10³) (± 1 × 10^–3)
   or V_o = ± 1 V

   Correct Option: C

   Output of the op-amp due to offset voltage of 1 mV
   

   Vo = –		1 MΩ		Vi
   		1 kΩ

   
   or V_o = – (10³) (± 1 × 10^–3)
   or V_o = ± 1 V

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