Deriving a formula for Impedance for an AC circuit

In summary, the conversation is about finding the impedance of a circuit with a series connection of R and L, and a parallel connection of C, and determining the value of ω for resonance. The person is seeking help and resources for understanding AC circuits and impedance. Suggestions are given to refer to class notes or textbook for equations and to use the equations for resistors, capacitors, and inductors to combine the impedance components. A link is also provided for additional resources.
  • #1
Battlemage!
294
45

Homework Statement



Find the impedance of the circuit (R and L in series, and then C in parallel with them). A circuit is said to be in resonance if Z is real; find ω in terms of R, L, and C at resonance.

Here is the circuit:

http://img382.imageshack.us/my.php?image=g...ccircuitgf5.png


Homework Equations



The objective is to derive the equation. I'm not really sure where to start.

The Attempt at a Solution



For whatever reason, I never covered impedance of an AC circuit in intro physics II. Now in my mathematical methods of physics class we have a problem that requires you to work with it. I have no idea what to do here, and I'm certain something like this will be on the test next week. Basically, the only thing I am asking for is hints on where to start.

It would be appreciated if

a.) someone helped me with where to start

b.) someone posted links to remedial topics on AC circuits (as I said, we didn't not cover much with AC circuits in Physics II)


Thanks!
 
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  • #2
http://webhw.unca.edu/roberts_phys222/Content/chapters/s11/11_resonance.asp
 
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  • #3
Battlemage!, does your textbook or class notes give equations for the impedance of resistors, capacitors, and inductors separately?

Once you have those, they combine just like resistors do in terms of series and parallel components.
 

1. What is impedance in an AC circuit?

Impedance is a measure of the opposition to the flow of electrical current in an AC circuit. It is represented by the symbol Z and is measured in ohms (Ω). Impedance takes into account both the resistance and reactance of a circuit.

2. How is impedance different from resistance?

Resistance is the opposition to the flow of electrical current in a DC circuit, while impedance is the opposition to the flow of electrical current in an AC circuit. Unlike resistance, impedance takes into account the reactance of a circuit, which is the opposition to the change in current caused by the presence of capacitance or inductance.

3. What is the formula for calculating impedance in an AC circuit?

The formula for calculating impedance in an AC circuit is Z = √(R² + X²), where R is the resistance and X is the reactance. This formula is known as the Pythagorean theorem of electricity.

4. How is the concept of impedance used in practical applications?

Impedance is an important concept in the design and analysis of AC circuits. It is used to calculate the voltage and current in a circuit, as well as the power dissipation. Impedance is also used in the design of filters, amplifiers, and other electronic devices.

5. Are there any factors that can affect the impedance of an AC circuit?

Yes, there are several factors that can affect the impedance of an AC circuit. These include the frequency of the AC signal, the length and thickness of the conductors, and the presence of components such as capacitors and inductors. Temperature and humidity can also have an impact on the impedance of a circuit.

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