AC theory level 2 study guide 1

E(c)=?

E(c)=I x X(c)

In a parallel circuit that contains both XL and XC, the reactive currents add.

False

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The applied voltage will ? .

The applied voltage will remain the same if the frequency increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The phase angle will ? .

The phase angle will increase if the frequency increases

As frequency is increased in a parallel RLC circuit, the XL will ? , and the XC will ? .

increase / decrease

A circuit has a resistor and a capacitor connected in series and operating at a certain frequency. If the frequency is increased, the current ? .

increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The inductive reactance will ? .

the inductive resistance will increase if the frequency increases

In parallel RLC circuits, the ? is the same and is ? phase across all branches and is used as the main reference for calculations.

voltage / in-

A resistor and an inductor are connected in parallel. What is the phase relationship between the two voltages?

0° (in-phase)

Which of the vector diagrams shown below properly represents the resistor current, capacitor current, total current, and the location of angle theta for a parallel RC circuit that has a resistance of 470 ohms, a reactance of 330 ohms, and an applied voltage of 470 volts.

1 and 4

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads Power Factor = ? %

62.1%

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads ER = ? V

74.5 V

E(L)=?

E(L)=I x X(L)

E(t)=?

E(t)=E(l)-E(c)

In a parallel circuit, if XL equals 30 ohms and XC equals 40 ohms, the circuit will be capacitive.

False

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The power factor will ? .

The power factor will decrease if the frequency increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The resistance will ? .

The resistance will remain the same if the frequency increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The true power will ? .

The true power will decrease if the frequency increases

In a parallel RL circuit, the voltage across each branch is the same.

True

In a series circuit, if XL equals 30 ohms and XC equals 40 ohms, the circuit will be capacitive.

True

Resonance occurs at the particular frequency that would cause XL to be equal to XC in a circuit

True

The impedance of a parallel RL circuit is always less than the resistance or reactance of any one branch.

True

For a series RC circuit, the ? must be the same through all parts of the circuit.

current

In analyzing a series RLC circuit, the reference is the ? .

current

As frequency is increased in a series RLC circuit, the XL will ? , and the XC will ? .

increase / decrease

A circuit has a resistor and a capacitor connected in series and operating at a certain frequency. If the frequency is increased, the power factor ? .

increases

In a parallel circuit with the frequency applied below the point where XL equals XC, the circuit will act ? , and the line current will ? the line voltage.

inductive / lag

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The current will ? .

the current will decrease if the frequency increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The impedance will ? .

the impendence will increase if the frequency increases

The reference for analyzing a parallel RLC circuit is the ? .

voltage

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads XC = ? Ω

176.84Ω

In a parallel circuit, inductive current and capacitive current are ? out-of-phase.

180°

Given the circuit and parameters shown, solve for the following: (Round the FINAL answer to at least two decimal places in the specified unit.) I(t)= ? A

2.17 A

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads Z = ? Ω

225.55Ω

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads Angle θ = ? °

51.6°

Given the circuit and parameters shown, solve for the following: (Round the FINAL answers to at least two decimal places in the specified unit.) R=140 ohms E(t)=120 V f=60 Hz C=15 microfarads EC = ? V

94.1 V

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The voltage drop across the inductor will ? .

The voltage drop across the inductor will increase if the frequency increases

Determine how the following circuit characteristics will be affected if the frequency is increased in a series AC circuit containing a resistor and an inductor. The voltage drop across the resistor will ? .

The voltage drop across the resistor will decrease if the frequency increases

A resistor and an inductor are connected in parallel. If the voltage across the resistor is 120 volts, the voltage across the inductor is 120 volts.

True

In a series circuit with the frequency applied below the point where XL equals XC, the circuit will act ? , and the line current will ? the line voltage.

capacitive / lead

A circuit has a resistor and a capacitor connected in series and operating at a certain frequency. If the frequency is increased, the capacitive reactance ? .

decreases

A circuit has a resistor and a capacitor connected in series and operating at a certain frequency. If the frequency is increased, the impedance ? .

decreases

A circuit has a resistor and a capacitor connected in series and operating at a certain frequency. If the frequency is increased, the phase angle ? .

decreases