Please show answers and the working process. Thanks

 

 

EE 201
Homework set G
Due: Mar. 11, 2016
 Name___________________________ Sec _____________ 34. In the amplifier circuit below, the feedback network consists of the two resistors R1 = 5 kΩ,
and R2 = 50 kΩ.

Ro vs +
+ Ri – v1 +
+ Av
1
– –
vx vo –
R2 R1

 



a. Start by letting the model be ideal: Ri → ∞, Ro → 0, and A → ∞. Calculate the closedloop gain in that case.



G = vo/vs = ___________________________________



b. Then repeat with a model whose parameters are: Ri = 75 kΩ, Ro = 250 Ω, and A = 250.
Note: Do not try to analyze this as a feedback problem. Just use circuit analysis to find
the closed-loop gain. A couple of node equation might be one way to start. Recall that
the notes had similar examples with either Ri < ∞, or Ro > 0, but not both at the same
time.



G = vo/vs = ___________________________________
 R2 35. Calculate the gain for the inverting-type
circuit shown at right.







R1


vs


1 k!












G = vo/vs = ______________________________________ 2 k!
R3
1 k! –
+ R4
2 k! vo 36. Design a circuit using ideal op amps and resistors that takes three inputs, va, vb, and vc and
produces an output that is a weighted combination of the inputs:





vo = –8va + 6vb – 2vc.






 R2
1.5 k!
R1 –
37. Find the output voltage for the
2 k!
circuit shown.

+


Vs +
Is1
Is2


5V –
2 mA
6 mA
















vo = ____________________________________









If the amplifier saturates at vo = ±10 V, calculate a new maximum value for IS2 so that output
will not saturated.




 vo Vs1
15 V
38. Find the voltage vo1 and vo2 in the circuit at
right.





Recall: For an op amp with a negative feedback
loop, v+ = v–.









vo1 = ______________________________





vo2 = ______________________________






 +
– vo1
R1
500 ! Vs2
10 V +
– R2
2 k!
vo2
R3
400 !
R4
1 k! R5
5 k! va 
 
 
 39. The circuit at right might be called an “addervb
subtracter”. Find an expression for the output
voltage, vo, in terms of the 4 input voltages, va, vb, vc,
vc
and vd.



vd


















vo = _________________________________________ R1 20 k!
R2 18 k!
R3 30 k!
R4 20 k!
R5
20 k! R6 180 k! +
– vo

Attachments:

• 1496717983-hwG.pdf