EE 305 Final Exam
You have a circuit with four sources embedded. To find the total current through one of the resistors you use the principle of superposition. For this you take the following steps:
step 1: turn off all sources step 2: turn one source on step 3: find the requested current with the single source in the circuit step 4: turn the one source off again step 5: if you haven't turned on all sources yet, go back to step 2 and repeat with next source, otherwise proceed to step 6 step 6: add all solutions together to find the total current through the resistor
A band stop filter is designed to
stop all frequencies within a band of frequencies, w_1 < w < w_2
When using the concept of "virtual zero" we assume
that no currents enter or leave the input terminals and there is no voltage difference between the two input terminals.
You have a circuit with three sources. To find the total voltage across one specific resistor using the principle of superposition you need to find the voltage across this resistor
three times and add up the results.
An inductor is a device
which stores magnetic energy.
Given are the following complex numbers: z1 = 3 + j 4 z2 = 5 - j 10 z1 - z2 is given by
z1 - z2 = -2 + j 14
Given the complex number z1 = 15 < -π/2 What is its complex conjugate?
z1 = 15 < +π/2
Given the complex number z1 = 15 < π/2 What is its complex conjugate?
z1 = 15 < -π/2
Given is the following complex number: z1 = sqrt(2) + j * sqrt(2) (both numbers are square root of 2) This number is given in the polar form by
z1 = 2e^(jπ/4)
Given are the following complex numbers: z1= 2 e^(jπ/4) z2 = 5 e^(-jπ/2) Then z1/z2 is given by
z1/z2 = 0.4 e^(+j3π/4)
Given are the following complex numbers: z1 = 3 + j 4 z2 = 5 - j 10 z2 - z1 is given by
z2 - z1 = 2 - j14
Given are the following complex numbers: z1 = 2e^(j*π/4) z2 = 5e^(-j*π/2) Then z2/z1 is given by
z2/z1 = 2.5e^(-j*3*π/4)
Which relation is correct? 1/(1+j)=0.5-j0.5 1/(1+j)=0.5+j0.5 1/(1+j)=-0.5-j0.5 1/(1+j)=-0.5+j0.5
1/(1+j)=0.5-j0.5
Which relation is correct? 1/j=+1 1/j=-1 1/j=+j 1/j=-j
1/j=-j
The impedance of an inductor is given by
Z_L = jωL
What is the closed loop voltage gain of the amplifier below? (non-inverting)
A_V = 1 + R_F / R_S
The impedance of an inductor in series with a capacitor is given by
Z_LCseries = jωL + 1/jωC
an amplifier circuit, that combines several inputs and produces an output that is the weighted sum of the inputs is called
a summing amplifier.
Given is a parallel plate capacitor. It has a capacitance C1. If we double the distance between the plates the new capacitance C2 is given by
C2 =C1/2
Given is a parallel plate capacitor. It has a capacitance C_1. If we double the area of the plates the new capacitance C_2 is given by
C_2 = 2*C_1
We have two series capacitors, C_1 and C_2. The equivalent capacitance is
C_eq = (C_1*C_2)/(C_1 + C_2)
We have two parallel capacitors, C1 and C2. The equivalent capacitance is
Ceq = C1 + C2
Given is a long cylindrical coil. It has an inductance L_1. If we double the cross section of the coil the new inductance L_2 is given by
L_2 = 2*L_1
Given is a long cylindrical coil. It has an inductance L1. If we reduce the cross section of the coil to half of the old one the new inductance L2 is given by
L_2 = L_1/2
Given is a long cylindrical coil. It has an inductance L_1. If we use only half of the windings the new inductance L_2 is given by
L_2 =L_1/4
We have two series inductors, L_1 and L_2. The equivalent inductance is
L_eq = L_1 + L_2
We have two parallel inductors, L1 and L2. The equivalent inductance is
Leq = (L1L2)/(L1 + L2)
Given is the following complex power: S = (j131 + 183)VA The reactive power is given by
Q = 131VAR
An inverting amplifer V_s = 10V R_F = 15Ω What value do you need to choose for R_s to have a gain of A = -20?
R_s = 0.75Ω
Non-inverting amplifier V_s = 10V R_F = 2.4kΩ What value do you need to choose for R_s to have a gain of A=25?
R_s = 100Ω
The peak-value phasor corresponding to the following signal v(t) = 15V cos(ωt + π/2) is given by
V = 15Ve^(-jπ/2)
The peak-value phasor corresponding to the following signal v(t) = 25V cos(ωt + π/4) is given by
V = 25Ve^(jπ/4)
Apparent power is measured in
VA
Complex power is measured in
VA
Reactive power is measured in
VAR
The admittance of a capacitor is given by
Y_C = jωC
The admittance of a capacitor and a resistor in parallel is given by
Y_C||R = jωC + 1/R
The admittance of a resistor is given by
Y_R = 1/R
The admittance of a resistor in parallel with an inductor is given by
Y_R||L = 1/R + 1/jωL
There is an inductor L between the nodes i and j and while no other element connects these two nodes. For the dummy version of node voltage analysis, what is Y_i,j
Y_i,j = -1/(jωL)
There is a capacitor C between the nodes i and j and while no other element connects these two nodes. For the dummy version of node voltage analysis, what is Y_i,j
Y_i,j = -jωC
An ideal inductor is
a passive element.
To zero out a voltage source it must be replaced by
a short circuit
An inductor in a DC circuit can be replaced by
a short circuit.
A capacitor in a DC circuit can be replaced by
an open circuit
To zero out a current source it must be replaced by
an open circuit
You want to choose the signal of one particular TV station. What kind of filter do you use:
band-pass
A quantity that contains all the power information in a given load is the
complex power.
A capacitor
consists of two plates (usually of identical shape) facing each other at a distance and carrying equal but opposite charges.
The two input terminals of an operational amplifier are labeled as:
inverting and non-inverting
Usually the feedback loop connects the output terminal with the negative input terminal. This is called
negative feedback
An active filter consists
of an op-amp and the elements R, L and C.
A passive filter consists
of the elements R, L and C.
A high pass filter is designed to
pass all frequencies above the cutoff frequency w_c.
An amplifier is called non-inverting when
the source is connected to the non-inverting terminal.
An operational amplifier is
the source is connected to the non-inverting terminal.
