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