Electronics - Capacitors - Discussion
Discussion Forum : Capacitors - General Questions (Q.No. 5)
5.
What is the angle theta value for a 5.6 
F capacitor and a 50-ohm resistor in series with a 1.1 kHz, 5 Vac source?
F capacitor and a 50-ohm resistor in series with a 1.1 kHz, 5 Vac source?Discussion:
16 comments Page 2 of 2.
Krishnaa said:
1 decade ago
Power factor is the ratio of True power to the Volt-Ampere power.
When the circuit is pure resistive: true power = VA power.
With reactance : Reactive power comes into picture (VA power increases).
Which means impact of reactance in the circuit. This factor of increase in the Power is determined with concept of power factor.
In pure Resistive circuits: V and I are in same phase.
With Reactance : Phase lead/lag occurs (phase difference).
So, cosine of phase difference (cos°) which is literally equivalent to R/Z from co ordinate system (real and imaginary axis).
When the circuit is pure resistive: true power = VA power.
With reactance : Reactive power comes into picture (VA power increases).
Which means impact of reactance in the circuit. This factor of increase in the Power is determined with concept of power factor.
In pure Resistive circuits: V and I are in same phase.
With Reactance : Phase lead/lag occurs (phase difference).
So, cosine of phase difference (cos°) which is literally equivalent to R/Z from co ordinate system (real and imaginary axis).
Makkkk said:
1 decade ago
What is power factor here give its importance?
Visakh said:
1 decade ago
For RC circuit, tan θ = -Xc/R
Xc=1/(2*3.14*(1.1*10^3)*(5.6*10^-6) =0.0258*10^3
also we have R=50 ohm
=> tan θ= -0.516
θ = tan-1 (-0.516)= -27.29 or -27.3
Xc=1/(2*3.14*(1.1*10^3)*(5.6*10^-6) =0.0258*10^3
also we have R=50 ohm
=> tan θ= -0.516
θ = tan-1 (-0.516)= -27.29 or -27.3
MUKUL MISHRA said:
1 decade ago
z= R+X
X=1/j*2*pi*f*c = -j*25.83
SO, z= R-j(1/2*pi*f*c) = 50-j*25.83
tan(angle)= img. part/ real part
= -25.83/50
angle = -27.32 degrees
X=1/j*2*pi*f*c = -j*25.83
SO, z= R-j(1/2*pi*f*c) = 50-j*25.83
tan(angle)= img. part/ real part
= -25.83/50
angle = -27.32 degrees
Girish said:
1 decade ago
That is tanθ =(Xc/R)
Nagashree said:
1 decade ago
We know tthat cos(angle)=Xc/R
Xc=(1/2*pi*f*c)
By substituting values will get cos(angle)=0.355
So angle=27.3
But in capacitor power factor is lagging so ans is -27.3
Xc=(1/2*pi*f*c)
By substituting values will get cos(angle)=0.355
So angle=27.3
But in capacitor power factor is lagging so ans is -27.3
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