Problem 52-1    Source:  Problem 32 - page 440 -    BOYLESTAD, Robert -    Book: Introdução à Análise de Circuitos - 10ª edição - Ed. Pearson Education do Brasil - 2004.

A circuit dissipates 100 W (average power) at 150 V (rms input voltage) and 2 A (rms input current). What is the power factor? Repeat the problem for a power of 0 W and 300 W.

Problem 52-2    Source:  Problem 33 - page 440 -    BOYLESTAD, Robert -   Book: Introdução à Análise de Circuitos - 10ª edição - Ed. Pearson Education do Brasil - 2004.

The power factor of a circuit is 0.5 delayed and the power dissipated is 500 W. If the input voltage is given by v = 50 sin(ωt + 10°), determine the input current.

Problem 52-3    Source:   Problem 11 - page 448 -    HAYT, William Jr, KEMMERLY, Jack E. , DURBIN, Steven M. -    Book: Análise de Circuitos em Engenharia - 7ª edição - Ed. McGraw Hill - 2008.

Determine the average power absorbed by each of the circuit elements shown in the Figure 52-03.

Problem 52-4    Source:   Problem 10.34 - page 255 -    NILSSON, James W. & RIEDEL, Susan -    Book: Circuitos Elétricos - 5ª edição - Editora LTC - 1999.

In the circuit shown in the Figura 52-04, the R resistor is set so that the dissipating power be as large as possible. The value of the voltage source is rms. Determine:

a)   the value of R.

b)   the power dissipated by R under the conditions of item a.

Problem 52-5    Source:   Problem 19 - page 449 -    HAYT, William Jr, KEMMERLY, Jack E. , DURBIN, Steven M. -    Book: Análise de Circuitos em Engenharia - 7ª edição - Ed. McGraw Hill - 2008.

Determine the average power supplied by the dependent source in the circuit shown in the Figure 52-05.

Problem 52-6    Fonte:  Problem 12.15 - page 262 -    EDMINISTER, Joseph A. -    Livro: Circuitos Elétricos - Ed. McGraw Hill - 1971.

In the circuit shown in the Figure 52-06, the load Z_L is constituted by a variable resistance R_L. Determine the value of R_L for which the source delivers the maximum power to the load. Determine the value of this maximum power, P.

Problem 52-7    Source:  Adapted of Problem 12.17 - page 262 -    EDMINISTER, Joseph A. -    Book: Circuitos Elétricos - Ed. McGraw Hill - 1971.

In the circuit shown in the Figure 52-07, the load connected to the terminals A-B consists of a variable resistance R_L and a capacitive reactance X_C, variable between 2 and 8 ohms. Determine the value of R_L and X_C which carry the maximum power transfer to the load. Determine the value of that maximum power supplied to the load.

Problem 52-8    Source:  Problem created by the author of the site.

Be a consumer where the voltage supplied by the energy distribution company is   220 ∠0° V (rms).    The impedance representing the entire consumer circuit is given by the complex impedance Z = 5 + j 9 Ω.   See the Figure 52-08. What is the value of the consumer's power factor and how to fix it to FP = 0.95?

Problem 52-9    Source:  Problem created by the author of the site.

The powers in a circuit are calculated, where the average power equal to P = 1 300 W and a power apparent value of S = 1 900 VA. After power factor correction, the measured apparent power was S_N = 1 410 VA. Find:

a)   the value of PF before and after correction.

b)   the value of Q (reactive power) before and after correcting the PF.

Problem 52-10    Source:  Problem 3 of the Electrical Circuits Test II - UFRGS - 1975.

In the circuit of Figure 52-10.1 we have:

1 - Load Z₁   ⇒   40 √2 kVA with PF = 0.707 in advance.

2 - Load Z₂ = R₂ + j X₂.

The reading of the instruments is:

V₁ = 1,000 √2   V,   V₂ = 125   V   and  W = 100   kW.

It is known that the global circuit is predominantly inductive. Determine:

a)   the values ​​of I₁ and I₂

b)   the values ​​of R₂ and X₂

Problem 52-11    Source:  Problem prepared by the website author.

A 200 V network is supplying 300 A to a given load. Connecting a capacitor bank 15 kVAR in parallel with the load the line current reduces to 250 A. Determine:

a)   the active or real power of the load;

b)   the PF of the load.

Problem 52-12    Source:  Problem prepared by the author of the site.

In the circuit of Figure 52-12.1 we know that:

1 - The A ammeter measures a current of 8 A.

2 - The V voltmeter measures a voltage of 160 V.

3 - The W wattmeter measures a real power of 916.5 W.

4 - The power factor of the circuit is 0.783.

Based on the information above, determine:

a)   the values ​​of X₂ and the power in the resistor R₂.

b)   the values ​​of R₁ and X₁

Problem 52-13    Source:  Problem prepared by the author of the site.

Knowing that the power dissipated by the circuit shown in Figure 52-13.1 is 960 W with PF = 0.6 capacitive and that 4 R = 3 X, determine the values ​​of R, X and X_C.