Electric Circuits Theory 2

This allows us to exchange a voltage source and a series impedance for a current source and a parallel impedance and vice versa

• Source transformations

Impedances connected in parallel can be combined into a single impedance by

• Adding the reciprocal of the individual impedances and getting the reciprocal

The equationZ1=Z1Z2+Z2Z3+Z3Z1Z1Z1=Z1Z2+Z2Z3+Z3Z1Z1is used when doing

• Delta-to-wye transformations-incorrect

The basic circuit analysis and tools covered in Electric Circuit Theory 1 cannot be used to analyze circuits in the frequency domain

• False

The equationi1+i2++in=0i1+i2++in=0is the statement of Kirchhoff’s current law as it applies to a set of sinusoidal currents in the

• Time domain

The solutionis used when the current response is determined to be

• Underdamped(incorrect)

The current through an inductor cannot change abruptly

• True

The equationv1+v2++vn=0v1+v2++vn=0is the statement of Kirchhoff’s voltage law as it applies to a set of sinusoidal voltages in the

• Frequency domain

For n inductor, the voltage and current are

• Out of phase, current lags by90°

The currents and voltages that arise when the inductor or capacitor is disconnected abruptly from its dc source are referred to as the ___________ of the circuit

• Natural response

The equation for neper frequency of the series RLC circuit is the same as the equation of the parallel RLC circuit

• False

A sinusoidal voltage is given by the expressionv=300cos(120πt+30∘)v=300cos(120πt+30∘) What is the period of the voltage in milliseconds?

• 1667 ms

A sinusoidal current source produces a voltage that varies sinusoidally with time

• False

The phasor voltage at the terminals of a resistor is the resistance times the phasor current

• True

This allows us to simplify a circuit comprised of sources and impedances into an equivalent circuit consisting of a current source and a parallel impedance

• Thévenin equivalent circuits (incorrect)

The impedance of an inductor is denoted by

• J(−1/ωC)J(−1/ωC)

In the circuit belowWill the response be overdamped, underdamped, or critically damped?

• Overdamped

The interconnected impedances can be reduced to a single equivalent impedances by means of a

• Norton equivalent circuits(incorrect)

A sinusoidal voltage source produces a voltage that varies sinusoidally with time

• True

For a resistor, the voltage and current are

• In phase

This is the number of cycles per second of the sine function

• Frequency

In the equationi=Imcos(ωt+θi),θii=Imcos(ωt+θi),θiis called the _____________

• Phase angle

The switch in the circuit below has been open for a long time At t = 0 the switch is closed Determine(i_0(0))

• 05 A

This is the square root of the mean value of the squared function

• RMS value

The voltage on a capacitor cannot change instantaneously

• True

The equation s2RLs+1LC=0RLs+1LC=0is the characteristic equation for the

• Series RLC circuit

In the figure, the voltage and the current are

• In phase

Impedances connected in series can be combined into a single impedance by

• Adding the individual impedances

For a capacitor, the voltage and current are

• Out of phase, current leads by 90°

The unit of inductance is named in honor of

• Joseph Henry

A ____________ consists of two conducting plates separated by an insulator (or dielectric)

• Capacitor

A capacitor is an open circuit to dc

• True

In the circuit below, the voltage and current expressions arev=160e−10tVv=160e−10tV,t≥0+t≥0+,i=64e−10tAi=64e−10tA,t≥0t≥0 Find R

• 25Ω25Ω

The unit for capacitance is named after physicist

• Michael Faraday

The nature of the roots s1and s2depends on the values ofaaandωω0

• True

The equations for resonant and damped radian frequencies for the series and the parallel RLC circuit are the same

• True

The voltage on a capacitor can change instantaneously

• False

The currents and voltages that arise when energy is being acquired by an inductor or capacitor due to the sudden application of a dc voltage or current source This response is referred to as the ____________

• Step response

The source transformations and the Thévenin-Norton Equivalent Circuits discussed previously in Electric Circuit Theory 1 are analytical techniques that can also be applied to frequency-domain circuits

• True

Find the equivalent inductance of the circuit below

• 18H

Which equation shows the natural response of the voltage of an RL circuit?

• I0Re−(RL)tI0Re−(RL)t

The neper frequency reflects the effects of the dissipative element

• True

The rules for combining impedances in series or parallel are the same as those for resistors

• True

When impedances are in parallel, they carry the same

• Phasor current

In the equationv=Vmcos(ωt+ϕ),ϕv=Vmcos(ωt+ϕ),ϕis called the _____________

• Phase angle

The formula for time constant is

• τ=LRτ=LR

The current through an inductor can change abruptly

• False

Which equation shows the natural response of the current of an RL circuit?

• (I_0Re^-{left(tfrac {R}{L}right)t})(wrong)

Compute the charge stored on a 33-µF capacitor with 20V across it

• 660µC

Which equation shows the natural response of the voltage of an RC circuit?

• V_0e^{-tfrac{t}{tau}V_0e^{-tfrac{t}{tau}

Find the equivalent capacitance of the circuit below

• 9µF(wrong)

The switch in the circuit below has been open for a long time At t = 0 the switch is closed Determine(i_0(t))

• (1e^{-250t}A, t ≥ 0)(wrong)

In the formulawe denoteaaas the

• Alpha frequency(incorrect)

In the equationi=Imcos(ωt+θi),Imi=Imcos(ωt+θi),Imis called the _____________

• Phase angle

For the circuit in the figure below, no energy is stored in the 100mH inductor or the 04μFμFcapacitor when the switch is closed The voltage response is

• Underdamped

In the equationi=Imcos(ωt+θi),ωi=Imcos(ωt+θi),ωis called the _____________

• Angular frequency

In the formulawe denoteωω0as the

• Resonant radian frequency

Whenthe response of a second-order circuit is

• Underdamped(wrong)

A sinusoidal current has a maximum amplitude of 20 A the current pases through one complete cycle in 1 ms The magnitude of the current at zero time is 10 AWhat is the frequency of the current in hertz?

• 1000 Hz

When impedances are in series, they carry the same

• Phasor voltage

The rules for delta-to-wye transformations for impedances are the same as those for resistors

• True

For the circuit in the figure below, no energy is stored in the 100mH inductor or thecapacitor when the switch is closed Which two are the roots of the characteristic equation? (Choose two)

• (-1400 - j4800) rad/s(1400 - 4800) rad/s

The time required for the sinusoidal function to pass through all its possible values is referred to as the____________of the cycle

• Period

If a 6-µf capacitor is connected to a voltage source with v(t) =20 sin 3000t V, determine the current through the capacitor

• 6cos3000t A(wrong)

The equationZ2=ZcZaZa+Zb+ZcZ2=ZcZaZa+Zb+Zcis used when doing

• Delta-to-wye transformations

The s2+sRc+1Lc=0sRc+1Lc=0is called the _____________ of the differential equation

• Characteristic equation

This allows us to simplify a circuit comprised of sources and impedances into an equivalent circuit consisting of a voltage source and a series impedance

• Delta-to-wye transformation (incorrect)