Post on 01-Jan-2016
Disclaimer: This review is based on clicker questions that directly relate to the lectures. The exam will also contain materials from the labs and pre-labs and it will not be multiple-choice.
If a topics isn’t covered in today’s class it doesn’t mean that that topics will not be on the exam. (We can’t cover 14 lectures and 7 labs in 50 minutes.)
The input impedance of an ideal ammeter should be
A) zeroB) infinityC) A well defined non-zero value (e.g. 1 or 1k)D) It should provide a constant currentE) should have a shiny red color
The input impedance of an ideal voltmeter should be
A) zero.B) infinity.C) a well defined non-zero value (e.g. 1 or 1k).D) It should provide a constant voltage.E) It should have a bright yellow color.
What is the output impedance of an ideal voltage source?
A) zeroB) infinityC) a well defined resistance, but not zero or
infinity (e.g. 1 or 1k)D) purely complex (i.e. non-zero reactive)E) potato
What is the output impedance Zout of this circuit?
A) R1 + R2
B) R1 – R2
C) R1R2/(R1+R2)
D) R1/(R1+R2)
E) R2/(R1+R2)
V
R1
R2
A
B
What is the output impedance Zout of this circuit?
A) 1/(1/R1+1/R2+1/R3)
B) R1 + R2 + R3
C) R1R2/(R1+R2)
D) R1/(R1+R2)
E) R2/(R1+R2)
V
R1
R2
A
B
R3
A) 0 VB) 2.5 VC) 3.3 VD) 5 VE) 7.5 V
10V
1MW
1 MW
The input impedance of many scopes is 1 MW. What voltage does a scope with 1 MW impedance measure across the lower 1 MW resistor?
Vin Vout
1k
1μF
What is the cut-off frequency fc (aka. the 3dB-frequency f3dB) of this circuit?
A) 159 HzB) 1 kHz C) 6.3 kHzD) 1 MHzE) None of the above
Vin Vout
1k
1μF
What is the gain G of this circuit at the cut-off frequency fc?
A) 0B) 0.5C) 0.7D) 1E) None of the above
Vin Vout
1k
1μF
Draw a bode-plot of this circuit from 1Hz to 1MHz. Draw the vertical axis as “power gain“ (|G|2 in units of dB) and make sure to label the axes correctly (including tick marks).
For the circuit below, it is observed that Vin >> Vout. The shape of Vin is shown at right. Which of the choices best represents Vout? (Note: Vertical axes are not to scale.)
What is the voltage at the inverting input?
A)
B)
C)
D)
R
Rf
V1
VoutR
Rf
V2
𝑅𝑓
𝑅+𝑅 𝑓
𝑉 1
𝑅𝑅+𝑅 𝑓
𝑉 1
𝑅𝑓
𝑅+𝑅 𝑓
𝑉 2
𝑅𝑅+𝑅 𝑓
𝑉 2
E) None of the above
Vin
Vout
The open loop gain of this op-amp is 105 and the open loop bandwidth is 10 Hz. What is the bandwidth of a voltage follower made with this op-amp?
A) 10 kHzB) 100 kHzC) 1 MHzD) 10 MHzE) Can not be determined
What is the (approximate) 3dB bandwidth of the circuit shown below if the transition frequency of this transistor is fT = 200 MHz. (Assume that Vin is appropriately biased, i.e. VBE ≥ 0.6V.)
A) 10 kHzB) 100 kHzC) 1 MHzD) 10 MHzE) Can not be determined
+20 V
0 V
Vout
Vin
2 k
100
16
For Vin as shown, rank outputs 1, 2, and 3 according to peak-to-peak amplitude from largest to smallest
A) 1 > 2 > 3
B) 1 > 2 = 3
C) 2 = 3 > 1
D) 2 > 3 > 1
E) 3 > 2 = 1
If you have a signal with ~1V amplitude but you know that your signal cannot deliver more than 1 nA of current, what device would you use to amplify it?
A) A bipolar transistor amplifierB) A J-FET amplifierC) A MOSFET amplifierD) A diode amplifierE) An inverting op-amp amplifier.
A) 0 VB) 4 VC) 5 VD) 6 VE) 10 V
What is Vout with the gate grounded (i.e. Vin = 0V)?
ID
VDS
VGS = 0V
VGS = -0.2V
VGS = -0.6V
VGS = -1.5V
4mA
3mA
2mA
1mA
5V
+10 V1k
Vout
Vin 0 V
A) 1B) 2C) 5D) 10E) 20
What is the maximum gain of this amplifier?
ID
VDS
VGS = 0V
VGS = -0.2V
VGS = -0.6V
VGS = -1.5V
4mA
3mA
2mA
1mA
5V
+10 V1k
Vout
Vin 0 V
20
For a triangular input voltage (from -10V...+10V), the output of circuit 2 is:
A) identical to that of circuit 1B) different; Vout2,pk-pk > Vout1,pk-pk
C) different; Vout2,pk-pk < Vout1,pk-pk
D) different; Vout2,pk-pk = Vout1,pk-pk
circuit 2circuit 1
Vin = –1 V. No load is attached to the circuit.
Vout is:
A) -2 V
B) +2 V
C) -5 V
D) +5 V
E) None of the above
A bipolar junction transistor (BJT) is
A) a current controlled current amplifier.
B) a voltage controlled current amplifier.
C) a current controlled voltage amplifier.
D) a voltage controlled voltage amplifier.
E) none of the above.
VinVout
You want to make a bode-plot of a piece of wire of length L.At 1 MHz you find that the phase between Vout and Vin is about 90°.
So how long does it take for an electric signal to travel from one end of the wire to the other?
A) No time at all.B) ~ 100 nsC) ~ 250 nsD) ~ 500 nsE) ~ 1 μs
L
29
For the specified Vin, the following three output signals Vout
were observed.
The graphs above, from left to right, could have been collected using circuits:
A) 3,4,1
B) 3,4,2
C) 1,4,3
D) 3,2,1
E) none of the above