Transcript Review_questionsx

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) zero
B) infinity
C) A well defined non-zero value
(e.g. 1 or 1k)
D) It should provide a constant current
E) 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) zero
B) infinity
C) 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
R1
B) R1 – R2
C) R1R2/(R1+R2)
D) R1/(R1+R2)
E) R2/(R1+R2)
A
V
R2
B
What is the output impedance Zout of this circuit?
A) 1/(1/R1+1/R2+1/R3)
R1
B) R1 + R2 + R3
C) R1R2/(R1+R2)
D) R1/(R1+R2)
E) R2/(R1+R2)
R3
V
A
R2
B
The input impedance of many scopes is 1 M.
What voltage does a scope with 1 M impedance
measure across the lower 1 M resistor?
A)
B)
C)
D)
E)
0V
2.5 V
3.3 V
5V
7.5 V
1M
10V
1 M
What is the cut-off frequency fc (aka. the
3dB-frequency f3dB) of this circuit?
Vin
A) 159 Hz
B) 1 kHz
C) 6.3 kHz
D) 1 MHz
E) None of the above
1k
Vout
1μF
What is the gain G of this circuit at the cut-off
frequency fc?
Vin
A) 0
B) 0.5
C) 0.7
D) 1
E) None of the above
1k
Vout
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).
Vin
1k
Vout
1μF
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.)
t
Vout
t
Vout
C
Vin
A
Vin
B
R
Vout
C
D
t
Vout
t
Vout
t
2k
+15 V
Vout is:
A) –3 V
Vin = 3VinV
B) –6 V
C) –9 V
D) –15 V
E) None of the above
6k
+
–15 V
Vout
What is the voltage at the inverting input?
𝑅𝑓
𝑉1
A)
𝑅 + 𝑅𝑓
𝑅
𝑉1
B)
𝑅 + 𝑅𝑓
𝑅𝑓
𝑉2
C)
𝑅 + 𝑅𝑓
𝑅
D) 𝑅 + 𝑅 𝑉2
𝑓
E) None of the above
Rf
V1
V2
R
Vout
R
Rf
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)
B)
C)
D)
E)
10 kHz
100 kHz
Vin
1 MHz
10 MHz
Can not be determined
Vout
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.)
+20 V
2 k
A)
B)
C)
D)
E)
10 kHz
Vin
100 kHz
1 MHz
100 
10 MHz
Can not be determined
Vout
0V
For Vin as shown, rank
outputs 1, 2, and 3
according to peak-topeak amplitude from
largest to smallest
Vcc = +10.0 V
1k
7k
B) 1 > 2 = 3
Vin (V)
C) 2 = 3 > 1
Vout, 1
E
1k
Vout, 2
B
Vin
A) 1 > 2 > 3
C
3k
Vout, 3
1.0
3k
D) 2 > 3 > 1
t
E) 3 > 2 = 1
–1.0
16
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 amplifier
B) A J-FET amplifier
C) A MOSFET amplifier
D) A diode amplifier
E) An inverting op-amp amplifier.
What is Vout with the gate grounded (i.e. Vin = 0V)?
+10 V
1k
ID
Vout
Vin
4mA
VGS = 0V
3mA
VGS = -0.2V
2mA
VGS = -0.6V
1mA
VGS = -1.5V
0V
A) 0 V
B) 4 V
C) 5 V
D) 6 V
E) 10 V
5V
VDS
What is the maximum gain of this amplifier?
+10 V
1k
ID
Vout
Vin
A) 1
B) 2
C) 5
D) 10
E) 20
4mA
VGS = 0V
3mA
VGS = -0.2V
2mA
VGS = -0.6V
1mA
VGS = -1.5V
0V
5V
VDS
Vin
1k
Vout
Vin
1k
Vout
1k
1k
+10V
+5V
circuit 1
circuit 2
For a triangular input voltage (from -10V...+10V), the
output of circuit 2 is:
A)
B)
C)
D)
identical to that of circuit 1
different; Vout2,pk-pk > Vout1,pk-pk
different; Vout2,pk-pk < Vout1,pk-pk
different; Vout2,pk-pk = Vout1,pk-pk
20
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.
Vin
L
Vout
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)
B)
C)
D)
E)
No time at all.
~ 100 ns
~ 250 ns
~ 500 ns
~ 1 μs
N4
A●0=
A) 0
B) 1
C) A
D) A
N5
A●1=
A) 0
B) 1
C) A
D) A
N6
A●A=
A) 0
B) 1
C) A
D) A
N7
A●A=
A) 0
B) 1
C) A
D) A
N8
A ● (A+B) =
A) 0
B) 1
C) A
D) B
E) A ● B
For the specified Vin, the following three output signals Vout
were observed.
Vout (V)
Vin (V)
Vout (V)
4.0
4.0
1
3
–4.0
4.0
1
t (s)
Vout (V)
3
4.0
1
t (s)
–4.0
3
1
t (s)
–4.0
3
t (s)
–4.0
The graphs above, from left to right, could have been collected
using circuits:
1
A) 3,4,1
2
R
B) 3,4,2
Vin
C) 1,4,3
3
4
R
Vout
Vin
Vout
Vin
R
Vout V
in
R
Vout
D) 3,2,1
E) none of the above
29
z1 and z2 are two complex numbers with:
𝑖𝜃1
𝑖𝜃
𝑧1 = 𝑧1 𝑒 , and 𝑧2 = 𝑧2 𝑒 2
A)
|𝑧1 | 𝑖(𝜃 −𝜃 )
𝑒 1 2
|𝑧2 |
B)
|𝑧1 | 𝑖(𝜃 +𝜃 )
𝑒 1 2
|𝑧2 |
C)
(|𝑧1 | − |𝑧2 |)𝑒 𝑖(𝜃1−𝜃2)
D) (|𝑧1 | + |𝑧2 |)𝑒 𝑖(𝜃1+𝜃2)
E) none of the above