circuits

For the circuit shown, the output voltage at any frequency can be expressed as a. Vout= (R/(sqrt(R^2+Xc^2)))*Vin b. Vout = 0.707Vmax c. Vout= (Xc/(sqrt(R^2+Xc^2)))*Vin d. Vout= 0.707Vin

a. Vout= (R/(sqrt(R^2+Xc^2)))*Vin

In a series RLC circuit, if the frequency is below the resonant frequency, the circuit will appear to be a. capacitive b. inductive c. resistive d. answer depends on the particular components

a. capacitive

A power factor of zero implies that the a. circuit is entirely reactive b. reactive and true power are equal c. circuit is entirely resistive d. maximum power is delivered to the load

a. circuit is entirely reactive

For the circuit shown, the output voltage will a. lead the input voltage b. lag the input voltage c. be in phase with the input voltage d. be out of phase with the input voltage

a. lead the input voltage

Given the impedance phasor diagram of a series RCcircuit, you could obtain the voltage phasor diagram by a. multiplying each phasor by the current b. multiplying each phasor by the source voltage c. dividing each phasor by the source voltage d. dividing each phasor by the current

a. multiplying each phasor by the current

Given the admittance phasor diagram of a parallel R Ccircuit, you could obtain the current phasor diagram by a. multiplying each phasor by the voltage b. multiplying each phasor by the total current c. dividing each phasor by the voltage d. dividing each phasor by the total current

a. multiplying each phasor by the voltage

Complex numbers can be expressed in polar form. Theangle is measured from the. a. positive real axis b. negative real axis c. positive imaginary axis d. negative imaginary axis

a. positive real axis

In a series RL circuit, the resistance phasor is plotted along the a. positive real axis b. negative real axis c. positive imaginary axis d. negative imaginary axis

a. positive real axis

The frequency represented by the red dashed line is the a. resonant frequency b. half-power frequency c. critical frequency d. all of the above

a. resonant frequency

A highly selectivity circuit will have a a. small BW and high Q. b. large BW and low Q. c. large BW and high Q .d. none of the above

a. small BW and high Q.

In an RL parallel circuit, the inductive susceptance isplotted on the -j axis. The reason for this is that a. the phase angle between Vs and I is -90° b. inductors are not ideal components c. current leads voltage in an inductor d. all of the above

a. the phase angle between Vs and I is -90°

The phase angle between the source voltage and currentin a parallel RL circuit will increase if a. the resistance is larger b. the inductance is larger c. both a and b d. none of the above

a. the resistance is larger

If you multiply each of the impedance phasors in a seriesRL circuit by the current, the result is the a. voltage phasors b. power phasors c. admittance phasors d. none of the above

a. voltage phasors

In a series RL circuit, there is a frequency at which the magnitude of the inductive reactance is equal to the resistance. At this frequency, the phase shift between the source voltage and source current is a. 0° b. 45° c. 90° d. 120°

b. 45°

The circuit shown is a. a lead network b. a low-pass filter c. both of the above d. none of the above

b. a low-pass filter

In a series resonant circuit, the resonant frequency can be found from the equation a. f=BW/Q b. f= 1/(2pi*sqrt(LC)) c. f=0.707*Imax d. f= 1/(2pi*LC)

b. f= 1/(2pi*sqrt(LC))

The basic filter circuit shown is a a. low-pass b. high-pass c. band-pass d. band-stop

b. high-pass

To multiply two numbers that are in polar form, a. add the magnitudes and add the angles b. multiply the magnitudes and add the angles c. add the magnitudes and multiply the angles d. multiply the magnitudes and multiply the angles

b. multiply the magnitudes and add the angles

In a parallel RLC circuit, the magnitude of the total current is always the a. same as the current in the resistor. b. phasor sum of all of the branch currents. c. same as the source current. d. difference between resistive and reactive currents.

b. phasor sum of all of the branch currents.

The magnitude of the admittance in a parallel R C circuitwill be larger if a. the resistance is larger b. the capacitance is larger c. both a and b d. none of the above

b. the capacitance is larger

At the cutoff frequency, the output of a filter is a. equal to the input b. −3 dB c. −6 dB d. −20 dB

b. −3 dB

At the critical frequency, the phase shift of a low-passfilter is a. 0° b. −45° c. +45° d. none of the above

b. −45°

In a series resonant circuit, the current at the half-power frequency is a. maximum b. minimum c. 70.7% of the maximum value d. 70.7% of the minimum value

c. 70.7% of the maximum value

A series resonant filter can be made into a a. low-pass filter b. high-pass filter c. band-pass filter d. none of the above

c. band-pass filter

The definition of a decibel is a.dB=10log(Pout/Pin) b.dB=20log(Vout/Vin) c. both a and b are correct d. none of the above

c. both a and b are correct

In a series RL circuit, the phase angle can be found fromthe equation a. theta = arctan(Xl/R) b.theta=arctan(Vl/Vr) c. both of the above are correct d. none of the above is correct

c. both of the above are correct

The maximum power factor occurs when the a. circuit is entirely reactive b. reactive and true power are equal c. circuit is entirely resistive d. product of voltage and current are maximum

c. circuit is entirely resistive

In a parallel R C circuit, the capacitive susceptance isplotted on an admittance phasor diagram along the a. positive real axis b. negative real axis c. positive imaginary axis d. negative imaginary axis

c. positive imaginary axis

In practical series and parallel resonant circuits, the total impedance of the circuit at resonance will be a. capacitive b. inductive c. resistive d. none of the above

c. resistive

f you increase the frequency in a series R C circuit, a. the total impedance will increase b. the reactance will not change c. the phase angle will decrease d. none of the above

c. the phase angle will decrease

In a parallel RL circuit, the magnitude of the admittancephasor can be expressed as a. Y= 1/(1/G + 1/Bl) b. Y= sqrt(G^2-Bl^2) c. Y=G+Bl d. Y= sqrt(G^2+Bl^2)

d. Y= sqrt(G^2+Bl^2)

The basic filter circuit shown is a a. low-pass b. high-pass c. band-pass d. band-stop

d. band-stop

A filter with the response shown is a a. low-pass filter b. high-pass filter c. band-pass filter d. band-stop filter

d. band-stop filter

If you increase the frequency in a parallel RLC circuit, the total current a. will not change b. will increase c. will decrease d. can increase or decrease depending on if it isabove or below resonance.

d. can increase or decrease depending on if it isabove or below resonance.

If a phasor that is expressed in polar form has an angleof -45°, it is in the a. first quadrant b. second quadrant c. third quadrant d. fourth quadrant

d. fourth quadrant

In an ideal parallel resonant circuit, the total impedanceat resonance is a. zero b. equal to the resistance c. equal to the reactance d. infinite

d. infinite

If you increase the frequency in a parallel R C circuit, a. the total admittance will decrease b. the total current will not change c. the phase angle between I R and I S will decrease d. none of the above

d. none of the above

If you increase the frequency in a parallel RL circuit, a. the total admittance will increase b. the total current will increase c. both a and b d. none of the above

d. none of the above

The measurement unit used with decibels is the a. watt b. volt c. ohm d. none of the above

d. none of the above

The phase angle between the source voltage and current in a parallel RLC circuit will be positive if a. IL is larger than IC b. IL is larger than IR c. both a and b d. none of the above

d. none of the above