Need help ASAP. PLEASE!!!

Please note that there's a figure containing following.


Figure: RLC series circuit with a Resistor and a Capacitor in parallel with an Inductor.

In the circuit the source delivers a sinusoidal output. For a particular frequency, the impedances are in the proportions of R : XC : XL is as 3 : 4 : 5.


R = 47 Ω, L = 3.3 mH, C = 3.3 µF. The input provided by the source is e = 3.4 sin 10000t V


a) Calculate the voltages across and currents through the other components – including phase angles taking the EMF from the source as reference.

b) Calculate the (apparent) Power input from the source and the power factor of the circuit.

Respuesta :

Answer:

All the calculations are shown in the explanation

Explanation:

RLC Circuit

The circuit proposed in the problem consists in one resistor R in series with the parallel of a capacitor C and an inductor L. All the impedances, voltages, currents and powers must be expressed as complex numbers since they all have an active and a reactive component. The formulas are very similar to those of the Ohm's law, as will be shown below.

The source has a time function expressed as

[tex]\displaystyle e=3.4\ sin\ 10,000t[/tex]

We must find the RMS voltage as

[tex]\displaystyle v_e=\ \frac{3.4}{\sqrt{2}}=2.4042\ V[/tex]

The given parameters of the circuit are

[tex]\displaystyle R=47\Omega[/tex]

[tex]\displaystyle L=3.3mH=0.0033H[/tex]

[tex]\displaystyle C=3.3\mu\ F=3.3\ 10^{-6}\ F[/tex]

[tex]\displaystyle w=10,000\ rad/s[/tex]

(a)

Let's find the reactances

[tex]\displaystyle X_L=wL=10,000(0.0033)[/tex]

[tex]\displaystyle X_L=33\Omega[/tex]

[tex]\displaystyle X_C=\frac{1}{wC}=\frac{1}{10,000(3.3150)}=30.30\Omega[/tex]

Now the impedances are

[tex]\displaystyle Z_R=47+j0[/tex]

[tex]\displaystyle Z_L=j33[/tex]

[tex]\displaystyle Z_C=-j30.03[/tex]

The equivalent impedance of the parallel of the capacitor and the inductor is

[tex]\displaystyle Z_{eq1}=\frac{Z_L\ Z_C}{Z_L+Z_C}=\frac{(j33)(-j30.03)}{j33-j3003}=\frac{1000}{2.9697}=-j336.73\Omega[/tex]

Computing the total impedance of the circuit

[tex]\displaystyle Z_t=Z_R+Z{eq1}=47+j0-j336.73[/tex]

[tex]\displaystyle Z_t=47-j336.73[/tex]

Converting to phasor form

[tex]\displaystyle Z_t=(340,-82.054^o)\Omega[/tex]

The given voltage of the source is

[tex]\displaystyle V_s=(2.4042,0^o)\ V[/tex]

It has an angle of 0 degrees since it's the reference. Let's compute the total current of the circuit

[tex]\displaystyle I=\frac{V_s}{Z_t}=\frac{(2.4042,0^o)}{(340,-82.054^o)}[/tex]

[tex]\displaystyle I=(0.00707,82.054^o)\ A[/tex]

We can see the current leads the voltage, so our circuit has a capacitive power factor, as shown ahead .

The voltage acrosss the resistor is

[tex]\displaystyle V_R=Z_R.I=(47)(0.00707,82.054^o)[/tex]

[tex]\displaystyle V_R=(0.3323,82.054^o)\ V[/tex]

The currents through the capacitor and inductor will be computed with the formula of the current divider .

[tex]\displaystyle I_C=\frac{Z_L}{Z_L+Z_C}\ I=\frac{j33}{j2.9897}(0.00707,82.054^o)[/tex]

[tex]\displaystyle I_C=(0.0786,82.054^o)[/tex]

[tex]\displaystyle I_L=\frac{Z_C}{Z_L+Z_C}\ I[/tex]

[tex]\displaystyle I_L=\frac{-j30.03}{j2.9697}(0.00707,82.054^o)[/tex]

[tex]\displaystyle I_L=(0.0715,-97.946^o)[/tex]

(b) The aparent power from the source is the product of the voltage by the total current

[tex]\displaystyle P_s=V_s\ I[/tex]

[tex]\displaystyle p_s=(2.4042,0^o)(0.007,82.054^o)[/tex]

[tex]\displaystyle P_s=(0.017,82.054)\ VA[/tex]

Finally, the power factor is

[tex]\displaystyle P_f=cos\ 82.054^o[/tex]

[tex]\displaystyle P_f=0.1382[/tex]

As mentioned before, since the current leads the voltage, the circuit is primarily capacitive

Otras preguntas