What is the relationship between voltage and impedance in electrical circuits?

In summary, the conversation discusses the phase difference between current and voltage in various components and how the angle is determined in each equation. The equation for the inductor's impedance is (jωL) and the phase shift of -90° is introduced by multiplying by -j. The phase angles of the other currents are determined by taking into account the phases of the voltage and impedance.
  • #1
nhrock3
415
0
http://i49.tinypic.com/ejyka9.jpg

i know that there is a phase difference between the current and its voltage for each
component
but here its between the voltage of the source and the impidance of each components

how did they get the angle in each equation?

in each equation we have Vm divided by some number
and the resolt is Vm and angle

how they get the coefficient of Vm
?
 
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  • #2
For the inductor, you know that the impedance is (jωL), and in this case, ωL = (5 ⨉ 103 rad/s )(0.2 ⨉ 10-3 H) = 1 Ω.

We're assuming a magnitude Vm for the (phasor) voltage, and taking its phase to be zero. Therefore, since the (phasor) current is given by the (phasor) voltage divided by the impedance:
IL = (Vm∠0) /(jωL) = (Vm) / (j)​

Now, dividing by j is the same as multiplying by -j. Multplying by -j is the same as introducing a phase shift of -90°. To see this explicitly, you can write j in complex exponential form (if you are familiar with it):

-j = e-j(π/2)

The phase angles of the other currents are determined in a similar way, by noting that current = voltage / impedance, and taking careful account of the phases of these two quantities.
 
  • #3
thanks :)
 

FAQ: What is the relationship between voltage and impedance in electrical circuits?

What is phase difference?

Phase difference is a measurement of the shift in timing between two waveforms or oscillations. It is typically measured in degrees or radians and can be used to describe the relationship between the two signals.

How is phase difference calculated?

Phase difference is calculated by finding the time delay between two waveforms at a specific point, typically a peak or zero-crossing. This time delay is then converted into degrees or radians based on the frequency of the signals.

What does a phase difference of 0 degrees mean?

A phase difference of 0 degrees means that the two signals are in phase, or aligned with each other. This indicates that the two signals have the same frequency and are synchronized.

What does a phase difference of 180 degrees mean?

A phase difference of 180 degrees means that the two signals are completely out of phase, or opposite to each other. This indicates that the two signals have the same frequency, but are completely inverted.

Why is phase difference important in science?

Phase difference is important in science because it can provide valuable information about the relationship between two signals and how they interact with each other. It is commonly used in fields such as physics, engineering, and electronics to analyze and manipulate waveforms and oscillations.

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