Currents and Phase relation in AC circuit with L, R, and C.

In summary, the question is about determining the currents in a circuit with a voltmeter reading of 100 volts and the phase relation between the applied voltage and one of the currents. The suggested solution is to convert all impedances and the source into phasors and use circuit analysis with complex numbers. A hint is also given, stating that the voltage source produces a waveform of 100 cos(120 pi t) volts.
  • #1
risendemon
8
0

Homework Statement



The voltmeter in the circuit sketched in the link below reads 100 volts. What currents would ammeters indicate for I1, I2, and I3? What is the phase relation between the applied voltage and I3?

http://i43.photobucket.com/albums/e394/risendemonx/prob3pic.jpg


Homework Equations



This is what I need help with, actually...

The Attempt at a Solution



So, I don't really want help in solving the problem, I just need a push in the right direction. Mostly something along the lines of what equations I need, or how to start going about looking at this problem. Anything at all will help me immensely

thanks a bunch!
 
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  • #2
Here's a hint: The voltage source produces a waveform of 100 cos(120 pi t) volts.

- Warren
 
  • #3
need to convert all impedances and source into phasors (complex number) first and do the usual circuit analysis with complex numbers.

eg: [tex]Z_L = j \omega L[/tex] where [tex]j=\sqrt{-1}[/tex] and [tex]\omega[/tex] is angular frequency.
 
  • #4
thanks so much both of you for your help! :-)
 

Related to Currents and Phase relation in AC circuit with L, R, and C.

1. What is the difference between AC and DC currents?

AC (alternating current) changes direction periodically, while DC (direct current) flows in only one direction. In AC circuits, the direction of current changes based on the polarity of the voltage source, while in DC circuits, the direction of current is constant.

2. How do you calculate the phase angle in an AC circuit?

The phase angle is the difference in phase between the voltage and current in an AC circuit. It can be calculated using trigonometric functions such as cosine and tangent, as well as using complex numbers and phasors.

3. How does the presence of inductors, resistors, and capacitors affect the phase relationship in an AC circuit?

Inductors and capacitors introduce reactance in an AC circuit, which can cause a phase shift between the voltage and current. In a circuit with only resistors, the voltage and current will be in phase. However, in circuits with inductors, the current will lag behind the voltage, while in circuits with capacitors, the current will lead the voltage.

4. What is the significance of the power factor in AC circuits?

The power factor is a measure of how efficiently a circuit uses power. In AC circuits, it is affected by the phase relationship between voltage and current. A power factor of 1 means that the circuit is using power efficiently, while a power factor less than 1 indicates that some power is being wasted due to reactive components.

5. How do you calculate the total impedance in an AC circuit with L, R, and C?

The total impedance in an AC circuit is the combined effect of resistance, inductive reactance, and capacitive reactance. It can be calculated using the formula Z = √(R^2 + (XL - XC)^2), where R is the resistance, XL is the inductive reactance, and XC is the capacitive reactance.

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