1. ECE Fun II Test 2 Review

2. ECE Fun II Test 2 Topics LTI systems
Input/output in time and frequency domains
Sinusoids, periodic, and transient functions
Impulse Response
Delta function properties
Convolution
h(ω)
Diodes
Ideal Model
Constant forward voltage drop model
Switch model
Exponential model
Use of diodes with opamps.
MOSFETs
Basic operation, terminals and polarities
Biasing
Small signal model
Transconductance
Assumed linear range
Common source amplifier

3. The impulse response is the output of a system when the input is a unit delta function.
True
False

4. The impulse response is the output of a system when the input is a unit delta function.
True
False

5. Whether or not the system is linear, the impulse tells us everything we need to know about the system.
True
False

6. Whether or not the system is linear, the impulse tells us everything we need to know about the system.
True
False

7. If the impulse response to the system is h(t), then the output of the system is the convolution of h(t) and the input x(t) except when the initial conditions are zero (at rest).
True
False

8. If the impulse response to the system is h(t), then the output of the system is the convolution of h(t) and the input x(t) except when the initial conditions are zero (at rest).
True
False

9. In convolution, when either function is multiplied by a step function u(t), the step function can be removed from the convolution integral by changing the limits of integration
True
False

10. In convolution, when either function is multiplied by a step function u(t), the step function can be removed from the convolution integral by changing the limits of integration
True
False

11. You are given the following circuit in the figure
You are given the following circuit in the figure. Assume that the op amp has infinite gain, unlimited bandwidth, but is bounded in output by VCC and VEE, where VCC is the most positive voltage in the system and VEE is the most negative voltage in the system. A B D C

12. You are given the following circuit in the figure
You are given the following circuit in the figure. Assume that the op amp has infinite gain, unlimited bandwidth, but is bounded in output by VCC and VEE, where VCC is the most positive voltage in the system and VEE is the most negative voltage in the system. A B D C

13. A system with input x(t) and output y(t)= x(0) + x(t). Linear?
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A system with input x(t) and output y(t)= x(0) + x(t).
Linear?
Time invariant?

14. A system with input x(t) and output y(t)= x(0) + x(t). Linear? A
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A system with input x(t) and output y(t)= x(0) + x(t).
Linear? A
Time invariant?

15. A system with input x(t) and output y(t)= x(0) + x(t). Linear? A
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A system with input x(t) and output y(t)= x(0) + x(t).
Linear? A
Time invariant? B

16. For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced.
Linear?
Time invariant?

17. Linear? B Time invariant?
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced.
Linear? B
Time invariant?

18. Linear? B Time invariant? A
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced.
Linear? B
Time invariant? A

19. For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied.
Linear?
Time invariant?

20. Linear? A Time invariant?
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied.
Linear? A
Time invariant?

21. Linear? A Time invariant? A
For the system described below determine if it is linear and time invariant.
Rubric: A: Yes
B: No
C: Cannot tell
A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied.
Linear? A
Time invariant? A

22. If V1 is 4.7 Volts and R1 is 4k Ohms, using the constant forward voltage model with Vdiode=0.7 V, the voltage across R1 is:
0 Volts
4.7 Volts
4.0 Volts
Not enough information to calculate it

23. If V1 is 4.7 Volts and R1 is 4k Ohms, using the constant forward voltage model with Vdiode=0.7 V, the voltage across R1 is:
0 Volts
4.7 Volts
4.0 Volts
Not enough information to calculate it

24. If V1 is 0.5 Volts and R1 is 4k Ohms, using the constant forward voltage model with Vdiode=0.7 V, the voltage across R1 is:
4 Volts
0.5 Volts
0 Volts
0.2 Volts

25. If V1 is 0.5 Volts and R1 is 4k Ohms, using the constant forward voltage model with Vdiode=0.7 V, the voltage across R1 is:
4 Volts
0.5 Volts
0 Volts
0.2 Volts

26. Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V
Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V. Assuming the Constant Forward Voltage Drop model, (CFVD, VF=0.7V) which of the following is true?
The diode current is approximately 0.5 mA.
The diode current is approximately 1.0 mA
The diode current is approximately 6.0 mA
None of the other choices is correct.

27. Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V
Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V. Assuming the Constant Forward Voltage Drop model, (CFVD, VF=0.7V) which of the following is true?
The diode current is approximately 0.5 mA.
The diode current is approximately 1.0 mA
The diode current is approximately 6.0 mA
None of the other choices is correct.

28. If R2=R3=1K, R4=R1=1000K, V1=10.7 V, and assuming the CFVD model, which of the following is true?
The diode current is approximately 5 mA.
The diode current is approximately 2.5 mA.
The diode is not conducting.
None of the other choices is correct.

29. If R2=R3=1K, R4=R1=1000K, V1=10.7 V, and assuming the CFVD model, which of the following is true?
The diode current is approximately 5 mA.
The diode current is approximately 2.5 mA.
The diode is not conducting.
None of the other choices is correct.

30. Which of the following best describes the display?
The system settings for the vertical scale should be increased, i.e. more volts per division.
The system settings  for the horizontal scale should be decreased, i.e. less time per division   .
Both the vertical and horizontal scales are set incorrectly.
None of the other choices is correct.

31. Which of the following best describes the display?
The system settings for the vertical scale should be increased, i.e. more volts per division.
The system settings  for the horizontal scale should be decreased, i.e. less time per division   .
Both the vertical and horizontal scales are set incorrectly.
None of the other choices is correct.

32. If the setting of the signal generator is 2 VP-P and the oscilloscope displays a 0.1 V amplitude signal, which of the following is true.
The probe setting is at 10X but the VB setting is at 1X .
The signal generator is set at 10X, and the probe is set to 1X.
The signal generator is set to 10X and the probe is set to 10X.
None of the other choices is correct.

33. If the setting of the signal generator is 2 VP-P and the oscilloscope displays a 0.1 V amplitude signal, which of the following is true.
The probe setting is at 10X but the VB setting is at 1X .
The signal generator is set at 10X, and the probe is set to 1X.
The signal generator is set to 10X and the probe is set to 10X.
None of the other choices is correct.

34. Assume that the circuit is operating in the saturated region for Q1
Assume that the circuit is operating in the saturated region for Q1. Which of the following is true?
If the value of RD is reduced by a factor of 2, the voltage gain will go down, approximately by 2 but the operating region will not change.
If the value of RD is increased by a factor of 2 the voltage gain will increase by 2 and the operating region will not change.
If R1 is decreased the operating region will not change.
None of the other choices is true.

35. Assume that the circuit is operating in the saturated region for Q1
Assume that the circuit is operating in the saturated region for Q1. Which of the following is true?
If the value of RD is reduced by a factor of 2, the voltage gain will go down, approximately by 2 but the operating region will not change.
If the value of RD is increased by a factor of 2 the voltage gain will increase by 2 and the operating region will not change.
If R1 is decreased the operating region will not change.
None of the other choices is true.

36. Assume that RD is 2K, RL is 100K and the overall voltage gain is 3 with a gm of 0.05S. The frequency of V2 is 100KHZ and the circuit is operating in mid-band and the small signal model applies. Which of the following is true?
The voltage gain will be relatively stable over significant changes in the values of the circuit parameters for Q1.
RS affects the value of the low-pass breakpoint associated with C2.
If R1 is decreased, the value of the gain will decrease, but the breakpoint frequencies for the overall circuit will not be affected.
None of the other answers is correct.

37. Assume that RD is 2K, RL is 100K and the overall voltage gain is 3 with a gm of 0.05S. The frequency of V2 is 100KHZ and the circuit is operating in mid-band and the small signal model applies. Which of the following is true?
The voltage gain will be relatively stable over significant changes in the values of the circuit parameters for Q1.
RS affects the value of the low-pass breakpoint associated with C2.
If R1 is decreased, the value of the gain will decrease, but the breakpoint frequencies for the overall circuit will not be affected.
None of the other answers is correct.

38. Using the values from the previous question, assume that a µF capacitor is placed in parallel with RS. Which of the following is true?
The voltage gain would increase to approximately 100, but the input signal would have to be reduced to stay in the range of operation for which the small signal model would apply.
The voltage gain would decrease dramatically as this capacitor would short the signal to ground.
The voltage gain would be unaffected, but the Q point would shift towards the triode region.
None of the other choices is correct.

39. Using the values from the previous question, assume that a µF capacitor is placed in parallel with RS. Which of the following is true?
The voltage gain would increase to approximately 100, but the input signal would have to be reduced to stay in the range of operation for which the small signal model would apply.
The voltage gain would decrease dramatically as this capacitor would short the signal to ground.
The voltage gain would be unaffected, but the Q point would shift towards the triode region.
None of the other choices is correct.

40. Which of the following is true?
By displaying a large number of cycles, the FFT math function will give a good approximation of the Fourier series for the displayed signal.
In order to get a good approximation of the Fourier series, it will be necessary to decrease the horizontal scale until no more than 3 cycles of the signal are displayed.
In order to get a good approximation of the Fourier series for the displayed signal, it will be necessary to decrease the vertical scale, i.e. fewer volts per division such that the peaks of the signal extend beyond the screen limits in order to minimize the effects of amplitude variations.
None of the other choices is correct.

41. Which of the following is true?
By displaying a large number of cycles, the FFT math function will give a good approximation of the Fourier series for the displayed signal.
In order to get a good approximation of the Fourier series, it will be necessary to decrease the horizontal scale until no more than 3 cycles of the signal are displayed.
In order to get a good approximation of the Fourier series for the displayed signal, it will be necessary to decrease the vertical scale, i.e. fewer volts per division such that the peaks of the signal extend beyond the screen limits in order to minimize the effects of amplitude variations.
None of the other choices is correct.

42. For an n-channel MOSFET, if the gate voltage is above the threshold voltage and is increased further:
The drain-source current will decrease and the saturation voltage will increase
Both the drain-source current and saturation voltage will increase
The drain-source current will increase and the saturation voltage will decrease
The drain-source current will decrease and the saturation voltage will decrease

43. For an n-channel MOSFET, if the gate voltage is above the threshold voltage and is increased further:
The drain-source current will decrease and the saturation voltage will increase
Both the drain-source current and saturation voltage will increase
The drain-source current will increase and the saturation voltage will decrease
The drain-source current will decrease and the saturation voltage will decrease

44. The drain-source current is linearly proportional to the gate-source voltage at a constant and small drain-source voltage.
True
False

45. The drain-source current is linearly proportional to the gate-source voltage at a constant and small drain-source voltage.
True
False

46. In the circuit below containing an n-channel MOSFET, if Vgs is increased, Vds will:
Decrease
Stay the same
Not enough information

47. In the circuit below containing an n-channel MOSFET, if Vgs is increased, Vds will:
Decrease
Stay the same
Not enough information

48. In the circuit below containing an n-channel MOSFET, if the power supply voltage is increased, the current through the drain resistor, R1, will:
Increase
Decrease
Stay the same
Not enough information

49. In the circuit below containing an n-channel MOSFET, if the power supply voltage is increased, the current through the drain resistor, R1, will:
Increase
Decrease
Stay the same
Not enough information

50. The n-channel MOSFET in the circuit below has a 4-resistor DC bias configuration. Assuming that Vin is a positive voltage and that Vgs>Vtn, Vgs will be:
Less than Vin
Equal to Vin
Greater than Vin
Can’t tell

51. The n-channel MOSFET in the circuit below has a 4-resistor DC bias configuration. Assuming that Vin is a positive voltage and that Vgs>Vtn, Vgs will be:
Less than Vin
Equal to Vin
Greater than Vin
Can’t tell

52. The gain of the MOSFET amplifier below depends on the Q-point.
True
False

53. The gain of the MOSFET amplifier below depends on the source resistor.
True
False

54. The gain of the MOSFET amplifier below depends on the source resistor.
True
False

55. The gain of the MOSFET amplifier below depends on the power supply voltage.
True
False

56. The gain of the MOSFET amplifier below depends on the power supply voltage.
True
False